420

This alloy is similar to ER410 but possesses a slightly higher chromium and carbon content. It is particularly used in overlay operations requiring corrosion resistance, due to the 12% chromium content, and offers increased hardness which enhances wear resistance. It is mainly employed in the creation of sealing surfaces for valves in pipeline systems used for gas, water, and steam, under service conditions up to +450 °C. Applications include the welding of similar base metals, overlays through welding and thermal spraying. It is also suitable for the coating of continuous casting rollers. If the parts are intended to remain in the as-welded condition, a ductile joint can be achieved by using austenitic consumables such as 22 12 L/309, 18 8 Mn/307 or 25 20/310.

Ferritic martensitic stainless steels.

The microstructure comprises tempered martensite and some carbide.

Corrosion resistant Cr-steels as well as other similar-alloyed steels with C-contents ≤ 0.30 % (repair welding), heat resistant Cr-steels of similar chemical composition.

• EN W.Nr.: 1.4006 (X12Cr13), 1.4021 (X20Cr13), +
• ASTM: 410, 420

Preheating and interpass temperature control during welding, followed by very slow cooling and post-weld heat treatment (PWHT), are crucial measures to prevent cracking. It is recommended to preheat the joints to a temperature between +200 and +300 °C, depending on the specific alloy and strength requirements. The interpass temperature should adhere to the same range. Heat input must be carefully controlled between 0.5 and 1.5 kJ/mm. The hardness of the deposit is influenced by the degree of dilution with the base metal and its chemical composition; in general, greater dilution and higher carbon content in the base metal result in a harder deposit. Post-weld heat treatment is essential for restoring ductility in the weld area, with tempering at +700 – 750 °C to improve toughness.