① Before surfacing, the surface of the surfacing part should be carefully cleaned with a steel brush, and there should be no defects such as oil, rust and scale.
② Before surfacing, the stacking surface of the surfacing part must be leveled to ensure an even distribution of the cast wc during surfacing.
③ When surfacing, the surface of the surfacing part is preheated by flame to form a very thin molten metal before surfacing.
④ When surfacing with oxygen-acetylene flame, the flame must maintain a slight excess of acetylene, oxygen: acetylene: 1:1.3, to protect the surface of the surfacing layer and the surfacing metal from oxidation.
⑤ Select the surfacing nozzle according to the size of the weldment and the degree of heating before surfacing. For example, if the medium-sized roller cone bit is welded, the suitable nozzle is used, the consumption of acetylene is 750 L/h.