Powder metallurgy material used for pressing and sintering exhaust seat ring

Abstract

The invention provides a powder metallurgy material used for pressing and sintering an exhaust seat ring. The powder metallurgy used for pressing and sintering the seat ring comprises the following components in percentage by mass: 0.8 to 1.3 percent of C, 1.5 to 3.0 percent of Cr, 1.0 to 3.0 percent of Mo, 3.0 to 6.5 percent of Co, 0.5 to 2.0 percent of Ni, 0.8 to 1.5 percent of MnS, 0.05 to 0.3 percent of P, 0.2 to 0.5 percent of V, 0.2 to 3.0 percent of W, and the balance Fe and unavoidable impurities. After the W is added, a hard particles is formed, and the power metallurgy material has higher wear resistance, impact resistance, corrosion resistance, and abrasion resistance at a high temperature, so that the bench testing time of the exhaust seat ring can reach 450 hours. Due to the addition of fatty acid diamide, the problem of furnace chamber scaling in a sintering process is solved; and by adding an anti-segregation agent and a free-cutting agent, the segregation of a finished product is avoided, the cutting is facilitated, and the size precision and surface roughness of a cutting surface are ensured.

Description

technical field [0001] The invention relates to a powder metallurgy material, in particular to a powder metallurgy material for pressing and sintering exhaust seat rings. Background technique [0002] The traditional valve seat is made by melting and casting various alloy elements, because the casting is melted at high temperature, so when it is cooled to room temperature, due to the difference in cooling rate between the core and the edge, the internal stress is relatively large, which is easy to produce processing and use out of shape. Because there are metals with different densities in the formula, it is impossible to combine and dissolve completely uniformly during the melting process. The metal compounds with high density must sink to the lower layer, and the metal compounds with low density must float on the upper layer, which causes the segregation of components, and the structure is not good. Uniformity, uneven hardness and softness lead to uneven wear, resulting i...

AI Technical Summary

Problems solved by technology

[0002] The traditional valve seat is made by melting and casting various alloy elements, because the casting is melted at high temperature, so when it is cooled to room temperature, due to the difference in cooling rate between the core and the edge, the internal stress is relatively large, which is easy to produce processing and use out of shape

Because there are metals with different densities in the formula, it is impossible to combine and dissolve completely uniformly during the melting process. The metal compounds with high density must sink to the lower layer, and the metal compounds with low density must float on the upper layer, which causes the segregation of components, and the structure is not good. Uniformity, uneven softness and hardness lead to uneven wear, resulting in air leakage on the sealing surface, reducing power, increasing energy consumption and exhaust emissions

It is very likely that some inclusions and air bubbles are not discharged in the casting, which will cause pores inside the product, resulting in a decrease in mechanical strength, air leakage on the sealing surface, and serious fracture

Since the castings are produced in a molten state, the energy consumption is high, the efficiency is low, and some alloy elements that are resistant to high temperature and wear cannot be added

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