Iron-base heat- and corrosion-resistant brazing filler metals

Abstract

The invention provides at a low cost iron-base heat- and corrosion-resistant brazing filler metals which make it possible to braze parts made of a base metal selected from among various stainless steels, particularly ferritic stainless steels, at a practical temperature (of 1120 DEG C or below) and are excellent in the wetting property against the base metal and which can attain excellent resistance to corrosion by sulfuric acid or nitric acid and high strength without coarsening the structure of the base metal. An iron-base heat- and corrosion-resistant brazing filler metal characterized by comprising 30 to75wt% of Fe, at most 35wt%of Ni and 5 to 20wt% of Cr in a total content of Ni and Cr of 15 to 50wt%, and at most 7wt% of Si and 4 to 10wt% of P in a total content of Si and P of 9 to 13wt%, preferably, an iron-base heat- and corrosion-resistant brazing filler metal as described above, characterized by further containing 0.5 to 5wt% of Mo and / or 0.3 to 5wt% of Cu in a total amount of Mo and Cu of 1 to 7wt%.

Description

Technical field [0001] The present invention relates to an iron-based solder alloy composition. More specifically, it relates to various stainless steel (especially ferritic) base materials when manufacturing various heat exchangers such as EGR (exhaust gas recirculation) coolers. The brazing used for brazing is an iron-based heat-resistant and corrosion-resistant brazing filler metal with excellent heat resistance and corrosion resistance, good wettability to stainless steel substrates, high strength and low cost. Background technique [0002] The Ni-Cr-P-Si brazing filler metal of the following Patent Document 1 and Patent Document 2 proposed by the inventors has been widely used for brazing of stainless steel parts in the manufacture of various heat exchangers such as EGR coolers. weld. [0003] Patent Document 1: Patent No. 3168158 [0004] Patent Document 2: Patent No. 3354922 Publication [0005] However, in recent years, the type of stainless steel used in component base mate...

AI Technical Summary

Problems solved by technology

As an iron-based brazing filler metal for heat exchangers based on low-cost Fe, the following patent documents 3 and 4 disclose, but in the composition shown in the examples of patent document 3, it can be seen that Contents that are not practical such as high melting temperature and low strength

Since there is no example in Patent Document 4, it cannot be verified. However, since it contains 20% by weight or more of Cr, when brazing a ferritic stainless steel base material, it is expected that the structure (grains) of the base material will be coarsened, Situations where the strength of brazed parts decreases

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