A410S Stainless steel Category

[CoCoE]

I am confused with the category of ASTM A410S stainless steel. Whether this is coming under a martensitic category or ferritic category? And do I need to consider preheating while welding this to CS?

 

[EdStainless]

410S is the low carbon variant and it is ferritic.
(There is no overlap in C range between 410 and 410S)

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P.E. Metallurgy, Plymouth Tube

 

[metengr]

Yes, you will need to preheat similar to 400 deg F despite the lower carbon content.

 

[CoCoE]

But why API 571 and ASTM considering 410S as martensitic? Is it available in both types? Also I have seen in many places 410s is ferritic??

 

[metengr]

Because if you review ASME/ASTM SA/A 240 material specification, the 410S maximum carbon content is 0.08% by mass, the 410 range is 0.08% to 0.15% by mass. However, ASME B&PV Code, identifies the 410S as ferritic, based on a P-No 7 grouping designation, whereas, 410 is a martensitic grade and is under P-No 6 grouping.

 

[EdStainless]

Even though the carbon in 410S is too low to Q&T like a martenstitic you still need to treat is as one when you well to minimize the risk of cracking.
This is called being careful.

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P.E. Metallurgy, Plymouth Tube

 

[CoCoE]

This is one definition given for martensitic grades in ASTM A959-11.

"3.1.4 martensitic grade, n—metallurgical term meaning that
the material is capable of being produced in a distorted
body-centered cubic structure by conventional heat treating
and quenching, and that the quenched structure is capable of
conventional tempering. Martensitic grades are delivered in the
annealed (ferritic) condition or the hardened and tempered
(martensitic) condition."

So it may be ferritic or martensitic depnding on the heat treatment it undergoes, as per our demand??

 

[EdStainless]

With 410S if you quench it you may form a little bit of lean martensite, but it isn't very hardenable, not enough C.

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P.E. Metallurgy, Plymouth Tube

 

[Guest102023]

In time you will come to loathe both these alloys.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"