A kind of ultra-low hydrogen ceramic flux for chromium-molybdenum heat-resistant steel and its preparation method

Abstract

Ultralow hydrogen ceramic welding flux for chrome molybdenum heat resistant steel comprises the following components, by mass percent, 28%-35% of MgO, 6%-15% of CaO, 17%-22% of CaF2, 13%-20% of Al2O3, 5%-10% of SiO2, 1%-5% of K2O + NaO, 0.5%-3.5% of ferromanganese, 0.5%-2% of ferrosilicon, and 6%-8% of MgCO3. The ultralow hydrogen ceramic welding flux for the chrome molybdenum heat resistant steel contains magnesia, fluoride, silicate, carbonate, the ferromanganese and the ferrosilicon serving as reducing agents and quartz which improves slag detachability and appearance of welding seams. When the ultralow hydrogen ceramic welding flux for the chrome molybdenum heat resistant steel is used for welding, the electric arc is stable, the slag detachability in the welding seams is good, the appearance of the welding seams is attractive, and the surfaces of the welding seams are free of cracks, air holes, indentations and other welding defects.

Description

technical field [0001] The invention belongs to the technical field of welding materials, and in particular relates to an ultra-low hydrogen ceramic flux for chromium-molybdenum heat-resistant steel. Background technique [0002] It is known that chromium-molybdenum steel has special high-quality properties, and is often used to manufacture some high-temperature and high-pressure-resistant valves and pressure vessels. The low-alloy heat-resistant steel used in pressure vessels is mainly Cr-Mo. This type of steel not only has high temperature resistance, but also has good hydrogen corrosion resistance, but how to ensure that after welding, the welded joint has the same performance as the base metal under high temperature, high pressure, and various corrosive media conditions. Testing of welding materials. With the application of Cr-Mo series heat-resistant steel more and more widely, the safe and economical operation of pressure vessel steel and welded joints will play a key...

AI Technical Summary

Problems solved by technology

In order to obtain flux with high alkalinity and low hydrogen content, high-temperature sintering is adopted, which can remove all or most of the moisture (including crystal water) in the flux at high temperature, and can also increase the strength of the flux and reduce its fragmentation. Therefore, the surface where the flux absorbs moisture is reduced, that is, the moisture in the flux is reduced. However, after high-temperature sintering, the flux absorbs moisture seriously, and it is difficult to control the diffusible hydrogen content at a low level during the welding process.

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