HEAT TREATMENTIn order to reduce the risk of damage by hydrogen embrittlement the following isrecommended:Steel with tensile strength above 1400 N/mm2 (or corresponding hardness 415 HB)should not be electroplated with zinc by conventional methods.Severely cold-worked steel articles and articles of steel with tensile strength above1000 N/mm2 (or corresponding to hardness 300 HB) shall be heat treated within 4 hafter the coating.The time for the heat treatment depends on the dimensions for the articles and on thetensile strength of the material. Minimum times for heat treatment at 190 -210 °C aregiven in table 1.The heat treatment has a detrimental influence on the chromate layer. The heattreatment should therefore be carried out before the chromating.Articles sensitive to hydrogen embrittlement and with layer thickness >15 pm shouldbe electroplated in two stages. In the first stage a layer of 8 pm is applied. After thisfollows a hydrogen embrittlement relief operation, reactivating of the electroplatedsurface and finally electroplating to build the coating to the required layer thickness.