Quality Differences in the same or equivalent steel grades

Difference in Qualit by steel mills for the same steel grade
Difference in Qualit by steel mills for the same steel grade

For some reason, there are cases where the same steel grade is made all over the world, but imported only by a specific overseas manufacturer.

For example, A276 304 (ASTM) is equivalent to SUS304 (JIS) as a universal steel grade.

Nevertheless, we sometimes receive inquiries about a common, standard steel grade from Japanese manufacturers. Why is this?

The reason is that the quality varies, or more specifically, the uniformity of metallurgical structure varies from manufacturer to manufacturer.

Although steel grades have different names in different countries, they are theoretically compatible as long as they have the same chemical composition of carbon, silicon, and chrome in addition to iron.

However, if the structure of each material is not fine and uniform during the process of mixing the materials at high temperatures and then spreading them thinly with rollers, the subsequent processes may be affected. Typical differences in microstructure occur when heat is applied. Steel made in Europe or Japan may have no problem, but when heat-treated or laser-cut in other countries, it may warp (curl) or crack (loose a small tip), or it may not be as hard as European or Japanese steel.

Of course, this does not mean that non-European or non-Japanese steel is bad. If the warpage is within the acceptable range, there is no problem, and sometimes it can be brought to an acceptable level by changing the heat treatment or laser cutting method. What is important is to understand what specifications are necessary for the steel material to be used by calculating backward from the final product.

When we receive an inquiry, we will first ask about the purpose of use and the environment in which the material will be used. Although it takes time and effort, we are proud to be able to propose the most suitable steel grade that can be used safely for a long period of time.

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