High-performance pin fastener surface modification treatment technology

Abstract

The invention discloses a high-performance pin fastener surface modification treatment technology. At first, nitrogen, sulfur and chromium multi-elements penetration is conducted on a pin fastener part taking alloy structural steel as a matrix material, so that a compact alloying layer of a nitrogen-sulfur-chromium and ferrum compound which has the thickness of 20 to 50 micrometers and the hardness being not less than 0.1700 and is subjected to the neutral salt spray (NSS) test for at least 120 hours is formed on the surface of the pin fastener part; then, the surface of the pin fastener part is polished; and finally, the pin fastener part is subjected to low temperature oxidation to form a compact oxidation layer. In the invention, since the alloying layer of the compound adopts the structure in which the nitrogen, sulfur, chromium and ferrum multi-elements compound covers the compact metallurgical bonding layer, the pin fastener part has the excellent performances of low cost, high strength and toughness and corrosion resistance, and remarkably prolongs the service life under the harsh service work conditions such as heavy loads and outdoor corrosion.

Description

technical field [0001] The invention relates to a metal material surface treatment technology, in particular to a surface strengthening and modification treatment technology for pin shaft fasteners that can be applied to large and medium loads and outdoor corrosion service environments. Background technique [0002] The pin shaft is a kind of standardized fastener, which is widely used in engineering vehicles, logistics handling equipment, trains, production equipment and other projects, wharf logistics, machinery, metallurgy, chemical industry and other working arms, cylinders, oil cylinders and various pin coupling mechanisms The equipment, which can be statically fixed or connected relative to the connected parts, is mainly used at the hinge of two parts to form a hinge connection. The pin shaft is usually locked with a cotter pin, which is reliable in operation and easy to disassemble. At present, the domestic standard of the pin shaft is GB / T882-2008, and the internati...

AI Technical Summary

Problems solved by technology

[0005] (2) In the open-air corrosive environment, under the influence of many factors such as accumulation over time or high temperature, impact, improper operation, etc., the pin shaft and its shaft hole are often blocked by corrosion and fail, resulting in the shutdown of vehicle equipment, especially the rust of the pin shaft in the shaft hole , making it difficult to disassemble and maintain the equipment, which is more common in the southern coastal areas of China, and the economic loss of equipment is serious, so corrosion resistance protection is very important. At present, anti-rust oil, phosphating, galvanizing, chrome-nickel plating and other coatings are traditionally used for anti-corrosion

Since the shaft usually has no oil hole, for the pin shaft used in engineering and logistics vehicle equipment with heavy load and dynamic connection, the coating protection layer is easy to lose, crack, and peel off, and the anti-rust performance and reliability are low

[0006] If you only consider the technical requirements of heavy load and dynamic impact corrosion resistance, you can choose high-strength materials with better matrix anti-rust ability, such as high-strength special stainless steel (precipitation-hardening stainless steel series with tensile strength Rm≥800 Mpa, currently domestic The grades include 0Cr17Ni7A, 0Cr17Ni4Cu4Nb and 0Cr15Ni7M02Al, or 600 series in foreign countries), but the price of raw materials is expensive (usually more than 3 times that of alloy structural steel), the processing is difficult, and the economy is poor