(8) Standards regarding the baking process

(1) ISO standards

In ISO standards, hydrogen embrittlement relief of electro-galvanized steel is provisioned as follows.

a. Stress relief before plating

Stress relieving heat treatments are necessary for parts made with steel alloys with tensile strength higher than 1000N/mm2 (or hardness shown in note 2) that have been: extensively cold worked, annealed, ground, or subjected to severe machining. (Note 2: Hardness HRC30, HV295, HB280)

b. Heat treatment processes after plating

Post-plating heat treating is necessary for parts that are expected to receive stress and/or static loadings, and for parts that are produced by severe cold working processes. (Table 1) below shows the guideline for heat treating conditions. For parts produced from case-hardened alloys that may be negatively affected by the heat treating guideline, processes with lower temperature at longer durations are required.

(Table 1) Guideline for heat treating steel alloy parts after plating

(2) JIS standards

The JIS standards also defines post-plating heat treatment references as shown in Table 2 below.

(Table 2) Heat treating guideline for stress relieving