Piston rod and production method thereof as well as carbonitriding agent for piston rod surface treatment

Abstract

The invention relates to a piston rod and a production method thereof as well as a carbonitriding agent for piston rod surface treatment. The carbonitriding agent comprises the following components by weight percent: 20-24% of urea, 13-15% of thiourea, 10-14% of barium acetate, 24-27% of calcium carbonate, 22-26% of barium carbonate and 4-10% of lithium carbonate. The carbonitriding layer tissue comprises an oxide layer, a tectorium, a compound layer, an Austria layer and a diffusion layer. The carbonitriding agent has the beneficial effects of simple formula and low cost; the piston rod produced by using the carbonitriding agent is smooth in surface, low in roughness and is airproof, the piston rod compound carbonitriding layer is more than 32mu m in thickness and has the characteristics of high corrosion resistance and abrasion resistance, low rejection ratio and long service life; in the piston rod production process, thermal treatment and anti-corrosion treatment are completed once, treatment temperature is between 600 DEG C-700 DEG C, the piston rod production process has the advantage of optimizing the machining process; and nitriding time is shortened to 30-50 minutes, production period is shortened, and production cost is reduced.

Description

technical field [0001] The invention relates to a piston rod, a carbonitriding agent for surface treatment of the piston rod and a production method thereof. Background technique [0002] The existing nitriding process for heat treatment of piston rod surface mainly adopts nitriding method, which can be divided into gas nitrocarburizing, liquid nitrocarburizing, solid nitrocarburizing and ion nitriding. Large, environmental pollution, unstable quality of nitriding, difficult to form mass production, etc., are gradually eliminated by people. [0003] Gas nitriding is also widely used. The main advantages are easy to control the surface quality, simple operation and wide application, but the production cycle is long, the production efficiency is low, and the corrosion resistance is poor (the neutral salt spray test can reach 96 hours). At present, the domestic gas nitrogen carbon The fatal weakness of co-infiltration method is that the gas composition cannot be strictly contr...

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Problems solved by technology

[0007] At present, the common surface treatment is carbonitriding, the nitriding temperature is controlled at 560-580°C, the nitriding time is 60-120 minutes, the permeation layer is 12-22μm, and the surface Vickers hardness is 430-500. However, if the nitriding temperature is increased, it is difficult for the infiltrated layer to reach more than 30 μm. If the salt bath temperature is too high, the movement of nitrogen atoms and carbon atoms will accelerate, the formation of the infiltrated layer will be too fast, and the salt bath will volatilize too quickly, which will accelerate the aging of the salt bath. , the active nitrogen atoms and carbon atoms cannot be absorbed by the surface of the parts in time, the unabsorbed active nitrogen atoms and carbon atoms may be converted into inactive substances and precipitate on the surface of the parts, forming carbon black, which hinders the absorption of other active nitrogen atoms and carbon atoms process, so that the piston rod is prone to surface defects, resulting in thicker loose layer of the piston rod, low surface hardness, poor wear resistance and corrosion resistance

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