Stainless steel after annealing abnormal phenomenon and solutions

1.Stainless steel grays after annealing

Reasons:

1. The stainless steel surface or the charging boxes is not clean

2. Gas leakage in the heat treatment furnace muffle pot

3. There are some problems with the protective atmosphere, such as the ammonia decomposition mixed gas used is impure.

Solution:

Before annealing, clean the product and charging box, and check whether the heat treatment equipment is operating normally.

If it is found that the furnace pot is leaking gas or the ammonia decomposition furnace that provides atmosphere protection is abnormal, it should be repaired or replaced in time.

2.Stainless steel yellows after annealing

Reasons:

1. The conveyor belt transportation speed is too fast, resulting in insufficient heat preservation time.

2. Too many products are placed on the conveyor belt at one time

3. Insufficient ammonia decomposition gas to provide atmosphere protection, etc

Solution:

1.Make plans for the thickness, size, material and hardness requirements of stainless steel products

2.Heat treatment operation is carried out strictly in accordance with different products relative to the process

3. In view of insufficient protective gas, the ammonia decomposition furnace should be repaired or replaced in time

3.Stainless steel turns green after annealing

Reasons:

1. The purification tower of the ammonia decomposition furnace is not switched in time.

2. The product surface contains moisture.

3. Ammonia decomposition gas is impure

Solution:

1. Ammonia gas and purification tower are switched once every 2 days

2.Annealing heat treatment is performed after the product has no moisture

3. Check whether the gas switching is normal and whether the ammonia decomposition furnace needs to be repaired or replaced.