A contractor delivered three components, all are supposed to be in 1.4571. Part A is actually done in 1.4404 / (X2CrNiMo17-12-2) (according to pretty conclusive documentation). Part B is allegedly done in 1.4571 / (X6CrNiMoTi17-12-2), but the material looks like part A (shiny, silvery). Part C meanwhile is also allegedly done in 1.4571, but looks different (silvery gray). "Allegedly" means that for the documentation for parts B and C is far less conclusive.

So, from someone who has encountered both steels: Would I expect them to look the same?

Or, to rephrase my question: Part A and C look the same but, according to the documentation provided, should be different materials - does this tell me something is amiss?

  • I think it would be really tough to tell those two apart. Can you have a metallurgical lab test them? – Mark Jan 30 at 12:12
  • 1
    surface finish can be significantly impacted by different machining processes. – agentp Jan 30 at 12:46
  • @mart So, in your q first sentence, you say all parts should be made of the same material, then in the final sentence you say A and C should be made of different materials - we have no chance if you can’t get the info correct... – Solar Mike Jan 30 at 12:52
  • If Part A is certainly in the "wrong" material, ask the contractor to re-make Part A in 1.4571? Then you will have another point of reference for comparing the appearance. That said, I'd be surprised if you could make any meaningful decision on appearance alone, as even different batches of the same alloy could vary, not taking into account surface finish differences etc. – Jonathan R Swift Jan 30 at 15:18
  • Normally, I wouldn't think to tell apart steel (except galvanized vs. stainless) by sight, but that part C sticks out visually made me think I may be missing something. My guess right now is that the visual differences are dut to surface treatment/machining. – mart Jan 30 at 15:22
up vote 3 down vote accepted

Not familiar with Russian specs but these look like ( in USA names) 316 L and 316 ; If so , you could not tell them apart by appearance. Also , if they have similar composition tolerances to USA specs you may not be able to separate them with chemical analyses ; 316 may have identical composition to 316 L.

  • Ooops, missed the Ti in part B ; That makes it more or less the same as Part A - 316 L , functionally . Europe likes to use Ti in stainless , You can't separate them by appearance. You can separate them ( if there is any need) with analysis of Ti only ; Part B should have a little ( eg 0.1 % ) and maybe the other parts will not have Ti depending on the exact spec requirements. – blacksmith37 Jan 31 at 2:53
  • I tried to find GOST standards online but there is a fee. – blacksmith37 Jan 31 at 17:38

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