420

Sharing similarities with ER410, this alloy distinguishes itself through a slight increase in both chromium and carbon contents. Its utilization extends to a myriad of surfacing operations where a combination of corrosion resistance (attributed to its 12 percent chromium composition) and augmented hardness for heightened wear resistance is paramount. This alloy finds its primary application in surfacing the sealing faces of valves employed in gas, water, and steam piping systems, especially under service temperatures reaching up to +450 °C. Beyond this, its versatility encompasses various applications, including welding similar parental metal, weld overlay, thermal spraying, and the cladding of continuous casting rolls. Remarkably, if the envisaged application demands the use of parts in the "as-welded" condition, achieving a ductile joint is entirely feasible. This is achieved through the application of austenitic fillers, with options such as 22 12 L/309, 18 8 Mn/307, or 25 20/310 proving suitable for this purpose.

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

Implementing pre-heating and meticulous interpass temperature control during welding, coupled with a deliberate and gradual cooling process followed by Post Weld Heat Treatment (PWHT), serves as effective preventive measures against cracking. For joint welding, a recommended preheating temperature of +200 – 300 °C is advisable, the specific value depending on the alloy type and strength levels. Correspondingly, the interpass temperature should be maintained within the same range. Ensuring an optimal heat input is crucial, avoiding extremes with a recommended range of 0.5 – 1.5 kJ/mm. The hardness of the deposit is contingent upon the degree of dilution with the base metal and its chemical composition. Generally observed is the correlation where higher degrees of dilution and higher C-content in the base metal result in increased deposit hardness. Post-weld heat treatment becomes a requisite to reinstate ductility to the weld zone. This involves tempering at temperatures ranging from +700 – 750 °C, a process aimed at enhancing the toughness of the welded structure. This comprehensive approach guarantees the mechanical integrity and performance of the welded joints.