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Up Topic Welding Industry / Metallurgy / 430 or 410
- - By Ehsan (*) Date 12-28-2011 10:25
Today I was asked to search about that which one these materials is more suitable for source service, SS. 430 or 410?
In metallurgical view the 430 type has lesser carbon content and higher cromium content so it looks to have better corrosion resistance, but in NACE standard the 410 type is listed. This has made me confused, I was wondering that anyone could help me.
Thanks in advance.
Parent - - By ozniek (***) Date 12-28-2011 13:57
Hi Ehsan

I assume you are referring to "sour service". The issue with sour service is essentially linked to the hydrogen cracking resistance of a material. (Also other issues, but for our purposes H cracking will suffice.) For this reason, materials that are very hardenable tend to be less resistant to H cracking in service. Type 410 is martensitic, while type 430 is ferritic, so 410 can be heat treated to a higher stregnth, but care needs to be taken to make sure that it is not too hard when in sour service. NACE tells you under which conditions you can use which materials, which then will restrict you in terms of maximum strength, and post weld heat treatment requirements etc.

In your case, you need to decide what properties (from a design perspective) you need, and then see if you can get that from either of the materials you are looking at while still meeting NACE requirements. Generally the comparison will be:

Type 410: Higher strength, but potential cracking issues during welding, and generally requires PWHT.
Type 430: Lower strength results, and often very poor impact properties in thicker sections following welding.

Hope this helps.

Regards
Niekie
Parent - By Ehsan (*) Date 12-29-2011 17:57
Thank you very much, you've always been great at metallurgy!!!
Up Topic Welding Industry / Metallurgy / 430 or 410

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