关于不锈钢管你需要知道的一切
- 基本 SS 管道类型
- 不锈钢管的特性
- SS 管道应用
- 管道的 ASTM 规范
- 制造类型
- ERW SS 与无缝 SS 管道
- 基于形状的类型
- 测试和包装
- 基于应用的类型
- SS 管道在应用程序中的用途
- 压力管的特点
- 不锈钢 304/304L 管道
- 不锈钢 310/310S 管
- 不锈钢 316/316L 管道
- 不锈钢 317/317L 管道
- 不锈钢 321/321H 管道
- 不锈钢 347/347H 管道
- 不锈钢 904L 管道
- 不锈钢管价格
- 常见问题解答
自一百多年前不锈钢发展以来，它已成为世界上使用最多和最受欢迎的材料。由于不锈钢具有显着的耐腐蚀性，有助于增加铬含量的特性。抗性可以通过还原酸以及抗点蚀侵蚀（例如在氯化物溶液中）表现出来。维护成本低，熟悉光泽，是不锈钢管的理想材料。
这种多功能材料在广泛的行业中是必不可少的。这可能包含许多应用，特别是对于 SS 管道，以积极的特性使用户受益。
由两种以上化学元素制成的含铁合金称为不锈钢。它被广泛应用于广泛的应用领域。不锈钢合金基本上是铁、镍、铬含量丰富的钢合金。
不锈钢已经存在了几个世纪，因为它容易受到腐蚀并且在恶劣的条件下工作得更好。不锈钢在 1800 年代后期得到认可，结合了铁铬和提供的防锈性。因为，然后它被模制成不锈钢管，以便它被用于许多工业应用。
1912年，褐铁矿实验室的研究人员终于建立了马氏体SS合金。新材料被标记为 Staybrite。不锈钢合金由铁合金组成，铬含量最低可达 10.5%。您可以在市场上看到种类繁多的合金，它们唯一不同的是化学成分。合金元素为钛、镍、碳、铜、氮，可提高成形性、强度和其他 SS 性能。
不锈钢管有不同的产品类型，如焊管和无缝管。成分可能会有所不同，这使得它可以在各自的行业中使用。一般工业公司使用不锈钢管，经常使用。
基本不锈钢管类型
来看看不同场景下使用的不同不锈钢管类型-
无缝管
没有焊缝或接缝的管道称为无缝管。它可以承受强烈或极端的温度和压力。所有的坦克都去金属。无缝管得到广泛的应用，如天然气和石油应用。它们还用于机械和工程行业。这就是在他们到达客户之前使其具有多功能性的原因；他们接受了精确度的检验，以确保其高质量的保证。
焊管
几乎所有行业都使用焊管，因为它具有灵活性。然而，当涉及到高耐腐蚀性从而抵抗压力时，它们的成本更高。由于使用的材料种类，焊管重量轻。在支付费用方面，与其他管道方法相比，它们具有成本效益。
管道法兰
整个管道系统需要的另一个重要部分是管道法兰。管法兰有多种类型，如螺纹、半法兰、搭接接头和百叶窗。它们采用坚固的材料和耐用的材料，确保提供具有最高可靠性的高品质产品。
特点
耐腐蚀性
市场上几乎所有的不锈钢管都是铁基合金，其铬含量最低为 10.5%。当合金含有铬时，会在合金上形成自修复或保护性氧化层。不锈钢管通过形成氧化层获得了耐腐蚀性能。氧化层的自愈特性意味着无论采用何种制造方法都可以实现完整的耐腐蚀性。
即使管道表面受到任何损坏或切割，它也具有自愈能力并提供高耐腐蚀性。另一方面，由普通碳通过涂层或涂漆例如镀锌形成的保护层。底层钢材和腐蚀暴露在表面改性中。
不同的不锈钢管在不同的环境下，其耐腐蚀性的工作可能会有所不同。不锈钢管有两个共同的主要特点——它们具有抵抗力和含有铬，使其不受攻击。不锈钢管不受腐蚀性碱、酸和其他化学物质的影响。
含有高镍、钼和铬的管道等级显示出更高的耐腐蚀性。
耐低温（低温）-
低温下的耐低温性通过低于零级温度的韧性或延展性来衡量。与环境温度相比，奥氏体不锈钢在低温下的抗拉强度要高得多。它们还具有在恶劣环境中保持优异韧性的能力。
在低于零温度时，不应使用沉淀硬化、马氏体和铁素体钢管。在低温下，牌号韧性显着下降。在某些情况下发现，在接近大气温度时，低温电阻下降。
加工硬化
等级不锈钢管加工硬化的最大优点之一是它显着增加和增强了金属强度，并有助于实现冷加工。退火和冷加工相结合，易于采用，从而使制成的零件具有适当的强度。
热强度
在峰值或升高的温度下可以保持高强度。不锈钢管牌号含有大量的铬或硅，氮负责热强度。铬铁素体牌号可提供高热强度。
高铬含量的不锈钢管有助于在峰值或高温下抗结垢。
强度和成型性
不同等级的不锈钢管提供不同的强度范围。与温和强度相比，强度在软条件下保持不变。较软的奥氏体钢具有出色的延伸率和延展性。因此，它可以进行冷加工，从而得到具有广泛系列半加工的成品。为了达到最终状态，韧性和强度得到有效结合。
铁素体不锈钢管提供良好的延展性和强度范围。马氏体钢管经后续热处理后硬度高，强度高。
延展性
% 伸长率负责拉伸试验时的延展性。奥氏体不锈钢延伸率高。高加工硬化和高延展率使奥氏体不锈钢能够成型并在深冲等切断过程中工作。
高强度
与低碳钢相比，不锈钢具有更高的抗拉强度。双相不锈钢通常比奥氏体钢具有更高的强度。在马氏体等级和沉淀硬化等级中，可以看到最高水平的抗拉强度。与其他牌号相比，这些牌号具有双倍的强度。
磁响应
磁性反应一般是不锈钢的吸引力。奥氏体牌号是纯非磁性的，它可以通过冷加工在少数奥氏体牌号中感应出来。像 316 和 310 这样的等级通常在冷加工时是无磁性的。所有其他不锈钢等级都是磁性的。
高温和低温服务
不锈钢在加热时可以保持高比例的强度。它在非常高的温度下加热时会变色。因此，不锈钢管被用于极端温度的行业。管材强度会随着各种因素的减少而降低。在高温下可见缓慢而稳定的伸长型，具有耐阴险。
在接近 1100 摄氏度的温度范围内与燃烧产物接触时，它是耐用的。在某些过程中温度达到 -196 摄氏度，这可能会导致延展性和韧性的损失。特定的奥氏体不锈钢合金与镍合金基配合使用，使其成为理想的选择。
局部腐蚀-
应力腐蚀开裂或 SSC–
应力腐蚀开裂或SSC基本上是由于部件失效或变形引起的突然开裂。当遇到以下条件时会发生这种情况-
- 任何部件因残余应力而受到应力
- 管道没有足够的抵抗力
- 不锈钢管的制造方式使其具有高水平的抗应力腐蚀能力。
耐热和耐火
由于镍和铬合金牌号的组合具有在极高温度下抗氧化和保持强度的能力。
卫生
不锈钢管易于清洁，因此客户通常会选择它。可用于屠宰场、厨房、医院、食品加工厂等行业。
美观
不锈钢管光亮美观，外观时尚，经久耐用。
重量对力量的优势
由于冷加工的加工硬化特性，可以产生显着的强化。与传统牌号相比，双相牌号降低了材料厚度。
易于制造
使用现代技术，不锈钢管可以很容易地成型、加工、焊接、制造和切割。
抗冲击-
不锈钢的奥氏体微观结构在高温下提供高韧性。这就是它可用于低温应用的原因。
长期价值
如果您考虑不锈钢的总生命周期或整个生命周期，您会发现使用了最便宜的材料。不锈钢管可带来长期效益。
应用
现在你知道不锈钢为什么会被使用了，让我们看看它在什么样的行业中被使用-
石油和天然气
很明显，在天然气和石油工业中，技术和工具起着至关重要的作用。多年来，人们对耐腐蚀管道系统的要求进行了深入探索。超级双相和双相不锈钢管在石油和天然气工业中得到了广泛的应用。它在恶劣和恶劣的条件下显示出令人难以置信的耐腐蚀性。如果存在任何损坏，管道系统将无法使用，并且在更深的深度容易爆裂。这就是为什么建议在天然气和石油行业使用坚固的管道，以便在工业中使用。
核电
从原子核中收集能量绝非易事。我们使用的那种核反应堆通过水提供蒸汽，水被传递到海岸附近的旋转涡轮机，以获得用于冷却需求的能量。然后水通过不锈钢管道泵入反应器。这些管道满足海水中腐蚀性的需要或要求。为了防腐，不锈钢管必须合格才能服务于核电行业。
管道的 ASTM 规范
行业与标准齐头并进，这是一句老话。由于广泛应用范围的不同组织标准的变化，生产和测试得到可能会有所不同。买家首先要了解自己项目的不同行业规格的基础知识，下段一目了然。
ASTM
ASTM 代表美国测试和材料协会。 ASTM 国际提供服务标准和工业材料，涵盖工业领域的广泛领域。这个特殊的组织目前已为 12000 多个标准提供服务，这些标准已在全球各行各业中使用。
近 100 多个标准与不锈钢管道和配件有关。与其他标准组织不同，ASTM 涵盖几乎所有种类的管道。
Fox 的例子——全系列的管材作为美国管材产品进货。对于高温服务，无缝碳管按照适当的标准使用。与材料相关的化学成分和具体制造工艺的确定定义了ASTM标准。
允许的数量为镁、镍、碳等，按“等级”分列。
例如-A级和B级有助于识别碳钢管。此外，还可以根据法兰、管道、管件和螺母来排列ASTM等级。
ASTM 材料
A106 -这些规格用于高温服务
A335 – 高温用无缝铁素体钢管
A333 -用于低温用焊接和无缝合金钢管
A312 – 一般腐蚀工况和高温工况，采用冷加工焊管、直缝焊管和无缝管
ASTM 标准有助于测试、评估机械、安装要求、设计和指定管道。
基于制造的类型 - 焊接 ERW、EFW、无缝
用连续卷材或板材生产焊管包括在连续过程中在辊子或弯曲机的帮助下将板材或卷材卷成圆形截面。在大尺寸制造中可以使用填充材料来完成。与更昂贵的无缝管不同，焊接管更便宜。基本上有各种焊接方法，例如-
EFW – 电熔焊
战争遗留爆炸物 – 电阻焊
高频 – 高频焊接
锯 – 埋弧焊（螺旋缝或长缝）
在本节中，您将学习和了解 HFW、EFW、ERW 和 SAW 等管道制造工艺。从连续的卷材和带材生产焊管。为了生产成品管，首先使用混板机将卷材或板材卷成圆形。
然后将圆形部分转发到第二部分。在第二部分中，焊接设置有助于管道的焊接。通过适当的焊接工艺，可以在不使用或使用填充材料的情况下轻松焊接管道。与无缝管相比，焊接管通常便宜得多，但由于焊接接头而较弱。焊管生产大尺寸，没有上限。长半径弯头和弯头可通过焊管制造成型。
现在，您已经了解了通过滚压机进行管材的基本成型。这种类似的工艺可以用来生产厚SAW管。
SAW焊管生产工艺
外部填充金属如电极丝被用于连接成形板。已知根据管尺寸将单个纵向接缝结合在锯管中。然而，对于非关键工艺或低压服务，使用锯管。
焊接是在单缝 SAW 管道中通过埋入弧焊工艺完成的。对于室外，连续使用实心填充焊丝。然后从外面焊接管道。
在双缝 SAW 管道中，通过点焊将两半连接起来，这称为装配。有两个接缝背靠背负责双缝管。接缝是从管子的内外焊接而成的。多道焊通过厚管进行。
开卷机由钢板在螺旋环中的螺旋SAW管内成型。这个环是从管道的外部和内部焊接的。直径范围广，采用不同的制造工艺生产。
对于低压工艺，使用螺旋 SAW 管道。对于中压或高压服务，使用直锯管。与直管相比，螺旋管得到了利用。
然后在焊接后对整个管体进行热处理。然后对缝焊管进行许多无损检测，如UT和RT检测，以利用焊接材料的完整性。
完成后，它们将进行水压测试，以利用它具有在压力和强度下显示防漏密封的能力。然后，作为测试的最后阶段，由合格的检测工程师对管道进行尺寸和外观检查。
根据标准需要，在发送给尊敬的客户之前发布标记。
ERW/EFW焊管制造-
ERW/EFW 焊管是通过连续轧制方法形成的厚度较小的管。在这种方法中，金属带材从带材送入辊道，并在线组装。条形逐渐形成圆形截面。在教皇轧制端部，管子通过焊接机连续焊接。
HFW、EFW/ERW 使用焊接方法，不添加填充材料。但是，与填充材料一起使用的是EFW焊接方法。
ERW 管材生产工艺
在 ERW 焊接制造中，利用铜开发的两个电极来施加电流和压力。电极通常为圆盘形，当材料通过时会旋转。然后让电极保持牢固接触，使连续焊接成功。
低压大电流通常通过焊接变压器使用交流电源连接具有极端电阻的管道。然后加热使其通过电流达到熔点。管子的半熔融表面在外力作用下聚集在一起，形成熔合，从而形成均匀的焊接结构。
HFW 管道制造
为了开发焊接接头，高频电流被用于 HFW 焊接。然而，在EFW焊接过程中，利用外部高能电弧来开发焊接接头。然后使用修整工具修整或去除管道内外多余的焊接材料。
在焊缝管上采用局部热处理，以减少焊接的负面影响。一旦它清除了超声波测试。为了恢复管道的微观结构，采用感应加热方法。这种特殊的热处理称为后退火。
下一阶段，HFW管允许通过尺寸检验、外观、水压试验和检验工程师认证的包装试验。
ERW 和无缝不锈钢管的区别
电阻焊的制造之后是在其长度上滚动金属。通过金属挤压，无缝管被生产成所需的长度。 ERW是沿其横截面焊接的接头，而无缝管则是沿其整个长度的接头。
在无缝管中，整个制造过程是通过实心圆坯完成的，这不是焊接。无缝管加工成各种尺寸的壁厚和尺寸规格。这些管道用于石油和天然气运输、工业和炼油厂等高压应用。
电阻焊管一般为纵向焊接，通过卷材或带材制造。它用于中低压应用，如水或油输送。您可以获得各种长度的无缝或 ERW 管道的通用尺寸。根据需要或要求，我们为尊贵的客户提供涂层形式和裸形式的表面处理。
基于形状的类型 - 圆形、方形、矩形
不锈钢管提供基于类型的形状，如方形、圆形和矩形。下面简要讨论每种形状的不锈钢-
不锈钢圆管
我们制造的圆管一般为奥氏体级圆管，可通过电阻和熔合技术等常用方法进行焊接。冷成型时因晶粒尺寸出现可见的起伏表面，称为“桔皮”。
提供的不锈钢管由于采用铝和钛级别的组合而进行了改进，以便在最佳温度下使用。由于奥氏体显微组织，圆管能够提供室温和低温下的冲击强度。
不锈钢无缝圆管还表现出对甲酸、磷酸、硫酸、非氧化性介质和醋酸的耐受性。它还具有抗应力腐蚀开裂、焊接热、刀线、点蚀 - 被认为是受影响的区域攻击。此外，出色的耐腐蚀性使圆管制造成为可能。
对于天然气和石油生产中的套管生产，它具有更高的强度特性。一些已知的特点是操作一致、结构坚固、易于维护、价格合理且性能优越。
圆管的尺寸范围为 ½”-24” NB。它的等级为 TP-304/L/H、TP-321/H 等等。标准为 ASTM A249-A358-A269-A778-A409-A789-A790。商用的公差长度为6000mm，固定长度的公差长度为1200mm-12000mm。表面处理可以是固溶退火、拉丝、无缝、焊接、酸洗和镜面抛光。
我们还根据客户的规格和需求以合理的价格提供各种设计、形状和不同尺寸的圆管。已知的类型有不锈钢圆无缝圆管、钢EFW圆管、不锈钢圆ERW焊管和不锈钢ERW无缝圆管。
不锈钢方管
我们提供卓越的不锈钢方管，可在多用途设备中正常使用，例如经常在恶劣条件下使用。对于腐蚀性环境，如含氯化物介质、温暖的氯化海水以及酸性介质，这些管道尤其适用。
我们的生产工人在有效制造这些方管方面拥有多年的经验，以提供低成本和高质量的管材，并提供最佳的服务保证。它可以承受的温度为 600 华氏度，而碳含量则成为关键。
不锈钢方管在大约 700 华氏度的温度下被气体附着，在 500 华氏度的熔融硫磺侵蚀中附着。它具有与镍相似的耐腐蚀性，但具有更高的温度和工作压力，成本低，因为它具有优越的能力被加工。
我们提供的 SS 方形无缝管因其在相当大的温度和压力范围内保持韧性而著称。方管既耐腐蚀又耐酸。一些管道合金可以承受纯氧中的火焰。它既可以冷加工，也可以热加工。 SS 方焊管不需要热处理，以开发强度延展性的最佳组合，并最大限度地减少后续加工过程中的变形。我们根据客户的需求和需要以合理的价格提供各种尺寸、形状和设计的管道。
与不锈钢圆管相似，它也具有性能优越、价格合理、运行稳定、操作方便、结构坚固、质量上乘等特点。
方管的尺寸范围为 ½”-24” NB。标准为 ASTM A249 -A409-A789-A358-A269-A778-A790。商用的公差长度为 6000mm +/-30mm，固定长度为 1200mm-12000mm 和 +/-0.5mm。表面处理可以是拉丝、无缝、焊接、退火、酸洗和镜面抛光。有TP-304/L/H、TP-321/H等等级。
不锈钢矩形管
我们提供的 SS 矩形管显示出更高的耐受性；许多腐蚀性介质也具有良好的电、热和磁致伸缩特性。对于大气温度下的所有应用，纯未充气酸的腐蚀速率较低。在热溶液和浓溶液中，合理使用寿命的比率通常较高。
矩形钢管必须在硝酸介质中使用，只能在室温和室温下浓度为 0.5% 的溶液中使用。这些矩形管还用于耐海水腐蚀组件、冷却回路、弹药和冷凝器管。我们提供的不锈钢矩形无缝管很容易制成管板，这对于轻松制造管壳和换热器是必不可少的。
矩形管可以通过拉伸或落锤、液压、动力制动方法进行热成型和冷成型。不锈钢矩形焊接管用于船舶硬件中的管道、海水系统、热交换器和冷凝器。有时它用于螺旋桨、优质拖船的船体、曲轴、渔船和工作船。我们提供不同尺寸的矩形管，并根据客户的规格以实用的价格设计形状。
方管、圆管和矩形管的检测和包装
对管形进行的测试有破坏性测试、无损测试、正极材料测试、微观和宏观测试、化学测试/光谱分析、晶间腐蚀测试、扩口测试、水压测试。特殊管道检测有夏比试验、力学试验、硬度试验、拉伸试验、超声波试验、射线照相试验、压扁试验、点蚀试验和外观检查。
随产品提供的文件有商业发票、装箱单（如净重和毛重）、数量和标记、规格指南、熏蒸证书和编号。其他文件为 NABL 测试报告、符合 EN 10204 3.1 或 3.2 的 MTC 报告和保证书。
不锈钢管包装在木箱、板条箱、纸箱和箱子中，单独用拉伸膜包裹，螺旋缠绕纸管，托盘上的芯。
基于应用的类型 - 卫生管、机械管、压力管、抛光管
不锈钢管根据等级和用途用于多种应用。应用管道是通过根据行业类型或需要服务的目的选择的合金混合物制成的。不锈钢可用于例如飞机液压升降机或其他行业。
许多著名的工厂，如生产线或工厂，都使用不锈钢管，以方便设备的工作。为保证不锈钢的耐高温和耐压强度，必须据此选择。
它提供的一些独特性能是可持续和持久的合金钢，脆性小，防锈性高，耐低温和耐高温，磁导率低，更具美感。
Stainless steel is basically steel alloys with low percentage of chromium. The addition of chromium improves corrosion properties related to steel. The maintenance of steel pipes is really easy with oxidation resistance.
These metals never ever spoil other metals that come in contact and can be used in numerous application types. Pipe manufactory can be used in application where tough and harsh working is required.
Based on the pipe’s end usage, the types of pipes can be classified. It is classified in various grade types of pipes. Today, in the market numerous number of steel types are made available when it coems to gain desirable properties with added particulates.
Main Purpose of SS in Applications
The stainless steel pipe is best suited for applications where corrosion resistance required arises.
Martensitic or ferritic steel types contains chromium so that it can be used in heat treatment as well as annealing applications
The stainless steel pipe of austenitic type comprises of nickel and chromium content which provides more resistance for usage in harsh conditions.
Given below are basic stainless steel pipe types
Pressure pipes- Pipes that are produced through the combination of nickel and solid chromium are known as pressure pipes. High acidic features at high temperature are offered with seamless welded electric fusion and large diameter pipes. The pipes that get used to carry fluid at high level of pressures are known as pressure pipes.
Features of pressure pipe
It helps in transferring of fluid via input and output. It works well with forge fluids as well as tanks or pipe from mods. It has the capability to transfer multiple amount of fluid on similar pipe. It can filter fluid type on its output as well as input. It has smart distribution between outputs.
Sanitary pipes
The another type of Stainless steel that is related to high sanitation applications such as sensitive application is known as sanitary pipes. In industry this pipe type has highest priority for effective flow of fluid. The pipe possesses highest corrosion resistance and it doesn’t tarnish by providing maintenance ease. As per the application, various tolerance levels gets decided. Sanitary pipes with ASTMA270 grades get utilized.
Sanitary pipe gets produced using effective methods so as to make it hygienic fitting types. They are used due to its easy cleaning and it can be easily dismantled. Manual cleaning or CIP process can be executed. The place where bacteria harbor or form is limited by this pipe. The pipe has corrosion resistance. All sanitary pipes get measured in OD tube. You can measure the diameter of sanitary pipe if you hold it on your hand.
Most of the sanitary stainless steel pipes may be either 316L or 304 stainless steel pipes. The sanitary pipe fittings don’t have any tight radii, threads, or pockets. The sanitary fitting provides sanitary clamp or buttweld clamp.
Mechanical pipe
In mechanical pipe application, hallow parts, bearing parts and cylinder parts are used typically. The mechanical can be controlled easily to wide variety of sectional shapes like rectangular, square, and other shapes in adding up to regular or traditional shapes. The commonly used grade types in mechanical applications are A554 and ASTMA 511. Mechanical steel pipe gets utilized in machined as well as formed parts such as transportation, household equipment, aircraft, farm machinery, automotive machinery, and industrial applications.
The stainless steel pipes are available in wide range of sizes and grades. The formation of mechanical pipe can be achieved through austenitic stainless steel or other steel. The typical mechanical pipe has size in range of 1.5-9 inch.
Excellent machinability – Most of the mechanical pipe grades has excellent machinability with consistent properties so as to increase cutting speed, set up times and reduce tool wear.
Cutting service – The mechanical pipe can be offered by top manufacturer and producer in random lengths or any of the cut to fixed length that has a range from 2.5-6.5 m. .
Polished pipe
The polished stainless steel pipes get used in house facility precisely based on the specifications. Acclaimed enterprise engage in offering of comprehensive array of stainless steel polished pipes. The polished pipes help in reducing wear and tear on operating parts. It also helps in reduction of adhesion and contamination of surfaces of various equipments. The electropolished surface can be used in many applications.
The polished pipes offered helps in promoting cleaning as well as help in reduction of down time association. The polished pipes are offered internationally and nationally along with high quality material. The top manufacturer offer pipes in customized thickness and sizes as per client demand or requirement at marketing prices.
Stainless steel polished pipes inherit no additional coating, corrosion resistant, and finishing needed. For decorative and architectural application, the polished pipes play an important and crucial part. Consistent and uniform surface finishing of polished pipes can be created.
Some of the leading features of polished pipes are durability, smooth, fine fishing, top quality handlebars, corrosion resistance, and uniform surface and consistent surface, dimensional accuracy. Manufacturing of polished pipes can be soft or cold rolled, descaled, and polished rolls.
All the stainless steel Type based pipes such as mechanical pipe, pressure pipe, polished pipe and sanitary pipes gets utilized in number of applications based on application purpose.
Stainless Steel 304/304L Pipes
Because of the ability of stainless steel to resist rusting against harmful chemicals and tough environment, it has been remarkably been used in industries. It shows incredible resistance to alloying environment and components when exposed to it. Various sorts of stainless steel are served in industry for variety of purposes. Out of all those stainless steel products, stainless steel 304/304L pipes are the most preferred.
Each and every type of SS is graded in series. The series classifies different sort of stainless steel ranging from 200- 600. All the grade pipes are available in different properties from families such as Ferritic, austenitic, martensitic and duplex hardening stainless. High resistance and high strength toward corrosion is well shown by all stainless steel grades.
The given below info shows difference between two types available in market- 304 and 304L.
304 Type Stainless Steel
304 Type is one of the most widely utilized austenitic or non-magnetic stainless steel. It is commonly termed as “18/8” SS due to its compositions that may include 18% chromium and 8% nickel. The type 304 SS has welding properties and good forming properties like strength and strong corrosion resistance.
This sort of stainless steel shows good drawability. It is made available in various sizes and shapes with regard to other grade types. It can be exercised with no annealing. Type 304 is commonly used in food industry. It is ideal for milk processing, wine making and brewing. It is also used for pipelines for yeast pans, storage tanks, fermentation vats.
Type 304 stainless steel is found in tabletops, sinks, refrigerators, utensils, cooking appliance and stoves. It has the ability to withstand corrosion which got cased by various chemicals such as milk, meat and fruits. It can also be used for chemical architecture, heat exchangers, and chemical containers.
Type 304 got used in water filtration systems and mining systems.
304L Type Stainless Steel
Type 304L SS products are extra low carbon content products in comparison to 304 steel alloys. In 304L lower carbon content, harmful carbide precipitation and deleterious get minimized during the welding process. Therefore, the 304L products are known as “welded products” that works well in corrosive environment and it is also capable of eliminating annealing need or requirement.
The grade has lower mechanical properties compared to standard 304 grades. Like 304 stainless steel, it also gets used in wine making and beer-brewing. It has purpose beyond food industries. It is also ideal for metal parts such as bolts and nuts when exposed to brine water.
Testing
Magnetic response test- the product is kept under permanent magnet so as to see whether it got work well in cold working or not.例如。 – rolling, bending, and forming.
Nitric acid reaction- the nitric acid reaction is executed when the product is kept in strong nitric acid at room temperature. It is to see whether it can work in harmful or corrosive environment or not.
Molybdenum spot test- the steel is clean first using abrasive paper and a drop of standard solution is poured on it. Presence of Mo confirms darkening of the drop. It is to see whether it avoid skin and eye exposure or not.
Stainless steel 310/310s pipes
Stainless steel grade 310 pipes are basically medium carbon stainless steel that can be used for higher temperature applications such as heat treatment equipment and furnace parts. In continuous service, it can withstand temperature of 1150 degree C and in intermittent service, the bearing temperature is 1035 degree C. 310S is also known as low carbon version compared to grade 310.
Stainless Steel 310/310S Applications
The typical applications of grade 310/310S are- it is used in kilns, fluidized bed combustors, tube hangers and steam boilers, lead pots, and refractory anchor bolts. It is also used for food processing equipment, muffles, cryogenic structures, and retorst.
Grade 310/310s Properties
These grades comprises of 20% nickel, 25% chromium. This is what makes it highly resistant to corrosion and oxidation. Grade 310S are basically low carbon version that is less flat to embrittlement. It also shows sensitization in services. The highest and medium chromium and nickel content respectively make the stainless steel capable for reducing sulphuric atmosphere that contain H2S.
They are used widely in moderate carburizing atmospheres like in petrochemical environments. Heat resisting alloys are used in more severe atmospheres. Grade 310 is not at all recommended for quenching that use frequent liquids from thermal shocks. This grade type is often exercised in cryogenic applications because of low magnetic permeability and toughness.
In common with austenitic SS, these grades are not at all hardened through heat treatment. It can’t be hardened through cold work and is practiced rarely.
Chemical Compositions for Grade 310/310S
Grade 310 as well as grade 310S stainless steel has different chemical compositions which is summarized in the next paragraphs.
The grade 310 and 310 S has carbon, silicon, sulphur, manganese, phosphorus, nickel, and chromium. For each element that chemical composition is different.
Mechanical Properties of Grade 310/310S
The mechanical properties of 310/310S grades are summarized as- grade 0.2% proof stress, tensile strength, elongation and hardness with 205, 520, 40, and 225 respectively.
Physical Properties of Grade 310/310S
The physical properties of 310/310S stainless steel are summarized as- at room temperature density, electrical resistivity, shear modulus, poisson’s ration, electrical conductivity, and melting point respectively. Other physical properties that make it incredible product are relative magnetic permeability, coefficient of expansion, and thermal conductivity.
Fabrication of 310/310S SS
Grade 310/310S fabrication involves forging in temperature gap of 975-1175 degree C. At 1050 degree C heavy work can be carried out easily then a light finish got applied to the bottom. After forging, basically annealing is recommended so as to relieve stresses from forging process.
Machinability of grades
Grade 310/310S pipes can be machineable and the only problem is work hardening. It remove work hardening layer through slow speed as well as sharp tools. It can be lubricated. Rigid tools, heavy tools and powerful machining can be used.
Welding of grades
The grade 310/310S can be welded with electrodes as well as filler metals. Some of the welding process these grades readily suit are GTAW, SAW, GMAW. There isn’t any requirement for post heat and preheat for corrosion service.
Stainless steel 316/316L pipes
Grade 316/316L is basically a standard moly-bearing grade type that has got second position in importance to 304 grade types. Better overall resistance to corrosion is provided by molybdenum, particularly crevice corrosion and pitting resistance is also served in chloride environments.
Grade 316L is generally known as low carbon content of 316. It is immune to sensitization. That is why it is extensively utilized in heavy gauge weldable components.
There isn’t any price difference between 316 and 316L stainless steels pipes. Excellent toughness is offered by austenitic structure.
As Compared to nickel-chromium stainless steels, the 316L offer highest stress to rupture, creep and tensile strength at peak temperature.
Key properties-
The grade 310/310S has chemical composition with elements such as nitrogen, Molybdenum, silicon, Phosphorous, chromium, and manganese as well as carbon.
The mechanical properties are appropriate elongation, yield strength, hardness Rockwell B, and tensile strength. Physical properties are appropriate density, specific heat, thermal conductivity, electrical resistivity, and elastic modulus.
Corrosion resistance
Various atmospheric environmental ranges are offered in which the product works well. It is subjected to crevice corrosion and pitting corrosion in hot chloride environment. The product works well at 60 degree C for stress corrosion cracking. It shows resistant toward potable water at 1000mg/L under ambient temperature.
The 316 is regarded as “marine grade SS” however it is not at all resistant toward hot sea water. In marine environment, this product does inherit surface corrosion. This particular product comes in associated rough surface and crevice finish.
Heat resistance
In intermittent service, the product has good oxidation resistance. At 925 degree C it works well in continuous service. The grade 316 works well at 425-860 degree C and it is not recommended to use it in aqueous corrosion. Toward carbide precipitation, the grade 316L shows more resistance. It has higher strength at peak temperature and it shows pressure containing applications temperature exceeding 500 degree C.
Heat treatment
It is capable of working in solution treatment. It can be heated at 1010-1120 degree C and it can be cooled rapidly.
Welding
All standards grades can be welded using resistance and standard fusion methods. It can be welded with as well as without filler metals. The grade 316 has a requirement of post welding for corrosion resistance however no post welding annealing is required.
It isn’t weldable through oxyacetylene welding methods.
Machining
The 316L SS tends to work awesomely if machining is done. For constant feed rates and low speeds 316L is recommended.
316 is much easier to machining because of low carbon content.
Cold and hot working
It can be hot worked through hot working techniques. The temperature range 1150-1260 degree C is suitable for hot working temperatures. Some of the common working operations on 316L are drawing, stamping, shearing. Post work annealing is easily carried out via removing internal stress.
Hardening as well as work hardening-
- Toward heat treatment, 316L is not at all hardened. It can be only be hardened by cold working so as to increase strength.
- The grade 316/316L is well used in architectural applications, marine applications and pharmaceuticals.
Stainless Steel 317/317L Pipes
Grade 317
The stainless steel is in general known as super alloy steels. The product consists around 4 to 30% content of chromium. They can be easily classified into Ferritic, martensitic, austenitic steels as per the crystalline structure.
Grade 317 is tougher compared to other stainless steel. Chip breaker usage is recommended for machinability of grade. Constant feeds reduce the hardenability that is why low speed gets used.
The grade grade 317 steel pipes are all weldable through resistance and fusion methods. For this particular alloy, oxyacetylene is not all used. For obtaining good results, 317L or AWS E/ER317 filler metal gets used.
The grade 317 can be hot worked through common procedures used for hot working. At 1149-1260 degree C or 2100-2300 degree F, it can be heated but below 927 degree C is shouldn’t be heated.
Cold working is successfully done through heading, shearing, drawing and stamping. Reduction of stress can be achieved through annealing.
At 1850-2050 F annealing is done by cooling. Grade 317 doesn’t retort to heat treatment. However, it can be cold worked.
Some of the applications in which grade 317 gets used are textiles, chemical equipment, and pulping paper.
Grade 317L
Grade stainless steel 317L pipes are basically low carbon content pipes compared to grade 317 pipes. The grade has corrosion resistance and high strength and it can even produce strong welding because of low carbon content.
It has chemical composition in definite proportion with elements like silicon, sulfur, manganese, chromium, iron, molybdenum, carbon, and phosphorous.
Mechanical properties that contribute immensely to pipes and are poisson” ratio, tensile strength, yield strength, elongation at break and hardness.
Manufacturing process
317L manufacturing process require constant feeds and low speeds so as to reduce work harden tendency. The steel is generally tougher compared to grade 304. It is available with long stringy chip. It makes use of chip breaker. Welding is recommended through resistance and conventional fusion. Oxyacetylene welding must be avoided.
Another thing that could be performed is conventional hot working. The product is heat at temperature range of 1149-1260 degree C or 2100-2300 degree F. It is recommended not to heat it below 927 degree C or 1700 degree.
With grade 317L drawing, heading, stamping, and shearing is possible and elimination of internal stresses is done through post work annealing. At 1010-1121 degree C or 1850-2050 degree F, annealing is performed which is carried out then through rapid cooling.
However, the grade 317L shows no response toward heat treatment.
Some of the applications of grade 317 SS are nuclear fueled power stations, petrochemical process equipment, and condensers in fossil.
The elements in the grade 317/317L are Fe, Cr, Mo, P, S, C and Ni. The grade 317L has mechanical properties, which displays detail regarding tensile strength posson’ ratio; hardness, modulus of elasticity, yield strength and elongation at break.
The 317L exhibit excellent corrosion resistance for a comprehensive range of chemicals, such as acidic chloride environments. It also shows resistant to sulfuric concentration at 120 degree f. This grade is readily used for welding, due to low carbon metal and higher molybdenum content. It has properties as good weldability and good formability.
Stainless Steel 321/321H Pipes
Grade 321
The grade 321 is basically an austenitic stabilized 18/8 steel by titanium or niobium addition. They are not at sensitive toward intergranular corrosion upon heating that’s why they got used within range of 425-850 degree C. Grade 321 is the foremost choice of applications that require temperature range near to 900 degree C, with combined resistant to scaling, high strength, as well as phase stability to aqueous corrosion.
One of the modified versions of 321 is termed as 321H that has higher carbon content so as to offer improved and enhanced temperature strength. The limitation that 321 hold is that the titanium content can’t transport higher temperature arc. This is what makes it not recommended for welding.
Like other grades, 321 also offer welding and excellent forming characteristics that are readily roll or brake formed. It also exhibit excellent welding characteristics. For this grade type, post weld annealing procedure is not required. They show excellent toughness at cryogenic temperature.
For decorative applications, grade 321 steel pipes is not at all recommended because it is not polished well.
Key properties
The typical composition of grade 321 is S, Cr, Si, Mn, C, N and Ni. The mechanical properties of grade 321 contain appropriate amount of tensile strength, hardness, elongation, and yield strength. The physical properties may contain specified specific heat, electrical resistivity, mean coefficient of expansion, and density.
Corrosion resistance – This grade is superior if welded in annealed condition, but is not recommended for post weld annealed process. At 425-900 degree C, industrial application can be performed. At 60 degree C, the grade can be subjected to crevice corrosion and pitting corrosion as well as stress corrosion cracking in chloride environment.
Heat resistance- In intermittent service, it offers good oxidation resistance at 900 degree C whereas in continuous service the temperature is 925 degree C. it can even perform well at 425-900 degree C in aqueous corrosive conditions. Higher hot strength can be achieved through 321H which is particularly utilized for higher temperature in structural applications.
Grade 321H
The grade 321H stainless steel is purposeful austenitic steel it is stabilized toward carbide precipitation. It is especially designed so as to work in temperature range of 427-816 degree C or 800-1500 degree F. this grade is purely non magnetic and it can easily be hardened through cold working. In the alloy composition titanium is added so as to suppress boundary chromium precipitation as well as to reduce suspectibility toward intergranular corrosion.
The steel grade 321h pipe is well used in various applications such as jet engine parts, chemical processing equipment, and aircraft exhaust manifolds and stacks.
Both 321/321H is advantageous for extreme temperature services due to good mechanical properties. The grades also offers stress rupture and higher creep properties. It can be considered for intergranular corrosion and sensitization exposures.
Cold forming, hot forming as well as machining is possible for both grade types. Operations such as turning at high speed, cutting at high speed, and drilling at high speed are possible. Various tests get conducted on the pipes so that high quality product is offered to esteemed clients.
Stainless Steel 347/347H pipes
Grade 347
The SS 347 pipes are dimensionally accurate, durable, and sturdy and are available in impressively corrosion resistant feature. With international as well as national standards, these stainless steel 347 pipes got produced. The grade 347 also offers reliable sensitization resistance toward higher temperature.
The 347 stainless steel pipes are in general austenitic stainless steel grades with columbium and tantalum addition that contribute in giving outstanding intergranular resistance toward corrosion. The maximum percentage of chemical composition in grade 347 are – phosphorous (0.045), molybdenum (0.50), carbon (0.08), manganese (2), chromium (19), sulphur (0.03), and copper (0.50).
The 347 stainless steel pipes have forming capability and superior welding. The grade 347 gets utilized frequently in petroleum refineries, pressure vessels, heat exchangers, welded fabrications, and power generation. Typically 347 stainless pipes are utilized in development joints, head gaskets, rocket machine parts. The addition of columbium offers the grade 347 pipes good power so that it can combat weathering.
The grade pipes are offered in square, round, rectangular, and oval shapes. It is also offered in customized option to esteemed or global customers. The schedule of it may be SCH20,SCH60, SCH80, SCH160, SCH40, SCH30. The form may be fabricated, welded, LSAW or seamless pipes. The length may be double random, single random and cut length. The end of pipes may be treaded, beveled, or plain end.
Grade 347H
The grade 347H ss pipes is basically common stainless steel type that resembles properties with 321,304, 316, and it can be used well at elevated temperatures. Just like the stainless steel 347H also exhibit welding qualities, and excellent forming due to addition of tantalum and columbium for exceptional intergranular corrosion.
The alloy 347H also exhibit higher carbon variants that enable it to offer creep resistance at temperature range of 537 degree C for higher strength. The stainless steel grade 347H has improved corrosion resistance for strong oxidizing environments. The grade is basically non magnetic typically in annealed conditions and it can be hardened through cold working.
The stainless steel 347/347h is basically popular because they are utilized in aircraft engine components, petroleum refineries, heat exchangers, and high heat applications.
The stainless steel 347 and 347H pipes are available in both welded and seamless forms both in NB and OD sizes.
The outside diameter could be 6.00 mm OD – 250 mm OD, it can be customized upto 12’ NB. It has thickness ranging from 0.3 mm to 50 mm. Or else, it can be SCH XXS, SCH 160, SCH 80, SCH 10, SCH XS. The grade may have types as welded, CDW, fabricated, and seamless. The forms may be rectangular, square, round, “U” shape, or coiled pipes.
The length could be required length, double random and single random. It has end as beveled, treaded, and plain end. The end protection could be done into plastic caps. It has outside finish as No.8, and no. 1. The delivery condition could be cold drawn, annealed as well pickled or polished.
The inspection test report of grade 347/347H includes visual inspection reports, chemical reports, mill test certification, third party inspection and destructive test reports.
The full identification of pipes can be summarized as per the nominal pipe size, grade, schedule, specification, grade, heat number, method of manufacturer, and manufacturer’s name.
Stainless Steel 904L pipes
The stainless steel pipes grade 904L is in general non-stabilized austenitic steel that contain low carbon content. The high alloy steel when added to copper helps in enhancing strong acids resistance like sulphuric acids. The stainless steel of grade 904L possess crevice corrosion, and stress corrosion cracking. It is generally non-magnetic that offers toughness, excellent formability, and weldability.
The grade 904L generally posses, incredible amount of expensive ingredients like nickel and molybdenum. Presently, most of the applications employ grade 904L ss pipes that replace duplex stainless steel.
Corrosion resistance
The grade 904L SS exhibit excellent resistance toward chloride attack and warm seawater. Stress corrosion cracking is offered because of presence of higher composition of nickel. Moreover, copper addition to grades helps in developing resistance toward reducing agents and sulphuric acid in both mild and aggressive conditions.
The grade 904L has intermediate corrosion resistance between standard austenitic grades and super austenitic grades along with 6% content of moly. This particular grade is less resistant toward acids such as nitric acids. Followed by cold working, this steel grades have to be solution treated so as to achieve maximum stress corrosion under critical environment.
Heat resistance
The grade 904L offers high oxidation resistance. However, the stability of structure gets collapsed at temperature above 400 degree C.
Heat treatment
The grade is heat treated at temperature of 1090-1175 degree C which is then followed by rapid cooling. For hardening of grades, the grade is thermally treated.
Welding
The grade 904L is welded using conventional or traditional methods. This grade type not at all requires post weld as well as pre weld heat treatments. It can be presented toward hot cracking under constrained weldments. The grade can be used according to AS 1554.6.
Fabricated
The stainless steel 904L grade has higher purity of steel with sulphur in low content. Using standard methods, the grade can be machined. It can be bends under cold condition although, subsequent annealing, can’t be demanded in most of the cases. Fabrication is performed or carried out in severe stress corrosion.
Features of 904L pipes – the 904L steel pipes exhibit crevice corrosion and pitting corrosion resistance. The 904L steel pipes also have stress corrosion cracking. It has maximum service temperature at 450 degree C. Toward intergranular corrosion, good resistance can be offered as well. The type 904L pipe has weldability and formability. This grade type exhibit good oxidation resistance and the structure provide stability at high temperature above 400 degree C.
Its applications – the grade 904L has various application usages such as in house processing capabilities as well as industrial application. It is very well utilized in gas scrubbing plants, oil refinery components, paper and pulp processing industries.
It is offered in various specifications, dimension, standards, pipe sizes, types, form, and end. Like other pipes, the types are LSAW pipes, Welded, fabricated, and EFW pipes. The end is treaded plain or beveled end. Form are coiled pipes, rectangular pipes, round pipes, square pipes, and hydraulic pipes. It is tested and then packed with utmost care.
Stainless Steel Pipe Prices
Top manufacturer and supplier offer variety of stainless steel pipes both in welded and seamless pipe that includes cold drawn seamless and hot finished seamless pipe. The most offered stainless steel pipes are 304, 316, 309, 321, 317, 304L, 321H, and 347. These pipes are delivered worldwide with price quotation.
The pipes price is decided on basis of length, standard, specifications, type, form, and finish. The price can be in rupee, or in any other currency such as dollar. Global or international clients can cross check the price through helpline or contact number. Contact reliable and trustworthy manufacturer for further detailing.
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FAQ’s
What makes stainless steel real stainless?
Stainless steel contains around 10.5% chromium. This chromium then reacts with oxygen present in the air or surrounding to form a layer known as chrome-oxide layer which is invisible however strong so as to protect further oxygen. Higher chromium levels as well as alloy element addition like molybdenum and nickel improves surface layer. This is what improves corrosion resistance.
What causes difference between 18/10 and 18/8 stainless steel?
The very first element present in stainless steel is chromium i.e. 18 percentage chromium. The second element present in stainless steel in abundance is nickel i.e. around 8% nickels So, as the name given to 18/8 stainless steel. When the composition is higher the material possesses higher corrosion resistance. Both 18/10 and 18/8 contain nickel and belongs to “300 series”. The series 400 doesn’t exhibit corrosion resistance properties and is magnetic however 300 series is non magnetic.
Is it possible that stainless steel will get rust?
Stainless steel never rust, the regular steel gets red oxide over the surface of the pipe. The red rust is due to iron particle which gets contaminated over the stainless steel surface. The instructor can try solution of 2% hydrofluoric acid and 10% nitric acid at room temperature. Now the area must be washed.
Is there any difference between 316 and 304 stainless steel?
The 304 stainless steel has 18% chromium as well as 8% nickel. The 316 stainless steel contains 10% nickel, 16% chromium, and 2% molybdenum. In order to assist with corrosion molybdenum is added to it.
How magnetic stainless steel is?
Several or various stainless steel types are offered. The series belonging to 300 that contain nickel is purely non magnetic. Whereas the 400 series are magnetic as it contain no nickel but chromium.
What is “passivation”?
When chromium content exceeds around 10 ½% a layer of chrome oxide gets formed that protects oxygen diffusion on surface and a “passive” result can be obtained. It shows oxidation to resistance or corrosion. When 10% nitric acid and 2% hydrofluoric acid is dipped the passive oxide layer is developed.
Is it possible to weld stainless steel?
是的。 Various stainless steel available from us can be welded. The welding procedure may be different compared to other carbon metal. The stainless could be welded using electrode or filler rod.
Is it possible to “hardened” stainless steel?
是的。 Stainless steel with series 300 is easily “hardened” however it can’t be ‘work hardening”. That is why the material gets cold worked trough lighter gauges, and cold rolling down or “drawing” via die or altering operations Annealing of stainless steel help sin removing effect of work hardening. The 400 series contain two major stainless steel types. One is acknowledged as “Ferritic that has 430, 409, and 439 that can be hardened by conduct of heat. The other series is known as “martensitic” that has 403, 420, and 410 as basic grades.
What “L” designation implies in a grade?
The letter L after a particular grade such as 904L implies that that carbon content in the material is restricted to a max of 0.03%. The normal level has 0.08% max whereas it is 0.15% max. When welding is performed lower carbon level is used this assist in protecting chromium from getting depleted.
What is meant by stainless steel recycle content?
Yes it is 100% possible recycling of stainless steel. The stainless steel can be easily re-melted so as to form new stainless steel. The recycled stainless steel can be used to form new stainless steel between 65-80%.
What is meant by “annealed conditions”?
Usually, in conditions such as “annealed” conditions the stainless steel is sold. The 300 stainless steel series is not at all hardened through heat treatment however is can only be hardened via cold working. Heat treatment eliminates cold work that will automatically restore soft conditions.
What is meant by “CRES” term?
The CRES stands for Corrosion resistant steel and is designate to stainless steel.
Is it possible to utilize stainless steel at very high and low temperature?
Yes it is possible to utilize stainless steel at low as well as high temperature. It can also be used at temperature 1800 degree F to liquid nitrogen temperature.
What is meant by AISI specification for SS?
AISI stands for American iron and steel institute which is originated for 300 and 400 number system series. It is published with chemical analysis, physical properties, and mechanical property listing for individual grade. The most specifications are in ASTM or American society for testing material.
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