4130 is a low alloy, copper-coated steel wire designed for TIG, MIG and submerged arc welding of heat-treatable, low alloy steels such as the SAE 4100 series and 8630 as well as steel castings with similar hardening characteristics. A pre-heat temperature of 300°F-350°F is required for some of the higher carbon grades in order to prevent cracking. Many other grades can be welded without a preheat.