95% Spheradized 2 pass 4130

[nsanch01]

We’re getting quotes for a fine blank part that gets processed to “95% Spheradized. 2 pass 4130.”
I’m trying to understand what the callout means and how will I be able to tell from the material cert if it was spheradized to 95%, and what does "2 pass" mean?

[Kelly_Bramble]

We’re getting quotes for a fine blank part that gets processed to “95% Spheradized. 2 pass 4130.”
I’m trying to understand what the callout means and how will I be able to tell from the material cert if it was spheradized to 95%, and what does "2 pass" mean?

Welcome to EE..

"Spheroidizing: Spheroidite forms when carbon steel is heated to approximately 700 °C for over 30 hours. Spheroidite can form at lower temperatures but the time needed drastically increases, as this is a diffusion-controlled process. The result is a structure of rods or spheres of cementite within primary structure (ferrite or pearlite, depending on which side of the eutectoid you are on). The purpose is to soften higher carbon steels and allow more formability. This is the softest and most ductile form of steel. The image to the right shows where spheroidizing usually occurs."

Spheradized.jpg

[nsanch01]

Thanks a lot. So the "2 pass" would that involve running the steel through the heating process twice? What would the purpose of that be?

[nsanch01]

What does the 95% Spheradized auctually mean and how is it verified. I'm looking at a material certificate and it says that the steel is "SPH AN" meaning spheridized and annealed but it does not indicate a percentage. Should that be on there, and how is the steel evaluated to that percentage? how do they determine that?