Welding of different types of steels, part 3
Multiprocess welders who are to perform welding on low-manganese steels are aware that these steels are of the AISI type 1320, 1330, 1335, 1340, and 1345 designations. These steels come with carbon that is in the range of 0.18-0.48%, silicon that is in the range from 0.20-0.35%, and manganese that is in the range of 1.60-1.90%.
With this type of steels the commercial welder does not require usage of reheating when the carbon and manganese are of the low range. When the carbon is around 0.25% then the commercial welder needs to preheat the steel to 120-150oC. After the welding is required post-heat treatment.
When the arc welders are performing welding processes on low-alloy chromium steels, they know that these steels are of the AISI type 5015 to 5160 and electric furnace steels of 50100, 51100, and 52100. Here, in these steels the stick welder can expect manganese levels from 0.30-1.00%, carbon ranges from 0.12-1.10%, silicon levels from 0.20-0.30% and chromium levels from 0.20-1.60%. No special preparations and precautions are needed when the carbon is of the low range, however when the carbon and the chromium increase, the arc welder should organize a preheating of 400oC.
When the commercial welders are performing submerged arc welding process, it is necessary for them to match the composition of the base metal with the composition of the electrode. With this welding process should be used only a flux that does not adds or takes elements to the weld metal. During the submerged arc welding process, the preheating can be reduced due to the slower cooling rates and the higher heat input.
The flux has to be dry, while the base metal and the electrode must be clean. When gas metal arc welding process is performed, the electrode that is used should match the base metal. The shielding gas here should be used in order to avoid the excessive oxidation of the weld metal. During the
gas metal arc welding, the preheating should be similar to the one used in the shielded metal arc welding process.