ASTM Seamless pipe

从ASTM标准转换

Engineering specification is also a language, and standard specifications for material and processes are defined differently in each country in the world. To a new designer, steel grades might seem easy, where 316 stainless steel is one material and cast iron another, but there are variations in each of these categories of metal. Rumors abound about people receiving poor quality steels from other jurisdictions. It leaves some designers wondering if there is something intrinsic in the official standards in other countries that can lead to these complaints.

国际标准不会翻译金属金属，这是单词转化的方式。从一个标准转换为另一种标准时，几乎不可能找到给定类型的金属的相同组合物。问题变成了：您能找到同等的吗？这可能会令人困惑，因为每个命名的金属等级都有自己的化学和生产指南。

For people without a materials background, these differences can make the purchase of foreign-made metal seem iffy, like ordering an inferior knockoff. However, the quality of the grades of steel are as good, country to country. Understanding what makes a steel standard or specification can help a North American business navigate overseas production.

STEEL GRADES EXPLAINED

Metal alloys are a mixture of different proportions of elements. A standard includes the chemistry, or “recipe” for the alloy, documenting what different elements should be melted into it. Specific instructions may also be given on melting temperature, cooling, and treatment.

Published standards also record the mechanical properties of a specified metal. If it has been made correctly, a metal should not only have the correct chemical analysis, but also perform within the correct range in mechanical tests.

Steels contain iron and carbon. Standards for each grade of steel specify the proportions by weight of each of these elements, as well as any additional elements alloyed with them. These additions may create different characteristics: for example, chromium is present in stainless steel to help prevent rusting.

In most consumer metal standards, the proportions of each element are given an acceptable range, rather than a precise number. For example, the ASTM 1050 grade steel is so named because it is approximately .50% carbon by weight. However, the tolerance for carbon percentage in the ASTM 1050 standard is .48-.55%. A similar Japanese specification sets carbon between .47-.53%, and allows for silicon and other trace elements, whereas the ASTM standard does not.

钢质规格通常为碳，锰，硅，磷，硫，铬，镍和钼提供范围，没有为每个元素设定相同的范围。出于这个原因，来自不同组织的钢铁标准不是精确的匹配：公差仅重叠。如果一种钢指定的硫含量少于.007％，而另一钢则允许多达0.040％？在许多情况下，微小的变化并不重要，但根据金属的预期用途可能是相关的。

It is not just chemistry, but also processing, that changes the behavior of a metal. Metal is crystalline and forms grain microstructures as it cools. Chemistry, melting, cooling, and heat treatment all can change the grain of the metal. This directly influences tensile strength, hardness, and brittleness. Therefore, steel specification may also include the production steps needed to create particular microstructures, including martensite, austenite, or ferrite grains.

在一个标准和另一个标准之间进行替换时，熟练的冶金学家或工程师将根据机械性能评估可比的等级。工程师认为最终产品需要做什么以及在什么条件下。利用他们对化学的理解，预期的工作负载以及对产品将运行的条件的了解，他们可以在任何标准中找到针对产品要求的钢。所有公认的钢制标准通常都具有等效性的严格性，这使得这种翻译成为可能。

它不是一个出版标准的不同rds that are the source of poor-quality foreign metals.