larger---for what？

湖南科技大学YWK

in our company,bear rings after heat traetmented,they will become larger.
we use atmosphere protected continues net furnance,
use  propane(丙烷) carbinol（甲醇） nitrogen（氮气）as protected atmosphere.
bear outer rings' demensions at the range of 30mm to 130mm,after treated, the average largeness is 0.25%D.
is it nomarl?will it infulence the quanlity and serverce life?

bill_bush

ja, Distortion is unavoidable.
After heattreatment, the dimension usually change.

But this change or vary, also has regular patern.

So we need to follow these distortion regular(law).

The attachment file give  experience for gear ring.

flytom

Yes, distortion is a difficulty problem for heattreatment.

Although vacuum heattreatment could not avoid this problem!

less dietortion, less oxidation, are the purpose of heat treatment industry!

陆丰

The diameter of the ring-like work-piece heat–treated become larger,I think it is the normal phenomenon. you may reserve grinding allowance to solve.

tong

it's normal for the products that have cylinder shape go 'bigger'
you can collect this distortion date for the mass production, then, make allwance for the machining process.