Material surface treatment

1. Salt bath nitrocarburizing (TUFFTRIDEQPQ) technology

The TUFFTRIDEQ process involves simply pre-cleaning the parts and preheating them in the air to 350-450°C, and then performing nitrocarburizing in an alkali-hydrogen salt tank. The processing temperature is usually 580°C, and the temperature is generally maintained at 60- 120min, the temperature can be lowered or raised under special circumstances. The cooling is carried out in an oxidation-type cooling tank in the temperature range of 350-400℃, and then the workpiece is cleaned with jet hot water. In addition to the slow cooling rate, oxidative cooling is beneficial to the dimensional stability of the parts, but also has other benefits: ①Significantly improve the corrosion resistance; ②The product on the surface of the part in the alkali hydrogen salt tank produces an oxide film; ③Get better sliding performance.

After the oxidation treatment, the parts can be polished (TUFFTRIDEQP) or polished and then processed in the oxidation tank (TUFFTRIDEQPQ). During the subsequent oxidation treatment, the roughness of the polished surface will not change.

2. Ion Precipitation Diamond Film Technology

Deposit a layer of diamond-like carbon film on the surface of the finished tool or deposit a layer of diamond film on other substrates and then weld it on the surface of the tool. The principle of preparing diamond film is to first prepare ionic carbon and then recrystallize it on the surface of the workpiece. Due to the presence of amorphous carbon and graphite, in fact, diamond-like carbon films are obtained in most cases.

3. Thermal spraying technology (Guide: The superiority of high-speed milling mold CNC machining center is beginning to show)

Thermal spraying is the use of a heat source to melt or soften the sprayed material, and rely on the power of the heat source or an external airflow to atomize or push the molten particles into a sprayed particle beam, which is sprayed to the surface of the substrate at a certain speed. Coating process method.

During the spraying process or after the coating is formed, the metal substrate and the coating are heated to melt the coating on the surface of the substrate and diffuse or mutually melt with the substrate to form a spray welding layer that is metallurgically bonded to the substrate. For thermal spray melting.

The advantages of thermal spraying: diverse methods, extensive coating, unlimited workpieces, and simple process.

Types of thermal spraying: flame spraying, arc spraying, plasma spraying.

1) Flame spraying:

①Ordinary flame spraying: Using oxygen-fuel gas as the heat source, the spraying material is heated to a molten or semi-melted state, and sprayed on the surface of the pretreated substrate with a high-speed airflow to form a coating with required performance.

②Explosive spraying: first send a certain proportion of oxygen and acetylene gas into the spray gun, and then mix the nitrogen and the rest of the spray powder into the spray gun through another inlet. When the gun is filled with a certain amount of mixed gas and powder , There is an electric spark plug to ignite, causing the oxygen-acetylene mixture to explode, generating heat and pressure waves. The sprayed powder is heated while accelerating and hits the surface of the workpiece to form a dense coating.

③Supersonic flame spraying: A special flame spray gun is used to obtain high-temperature, high-speed flame flow to spray tungsten carbide and other refractory materials and obtain a spray coating with excellent performance.

2) Arc spraying technology

①Ordinary arc spraying: A process in which the molten metal wire is atomized with a high-speed airflow using an electric arc as a heat source, and sprayed on the surface of the workpiece at a high speed to form a coating. Its characteristics: excellent coating performance, high efficiency, energy saving and economical, safe use.

②Supersonic arc spraying: It is a newly developed surface treatment technology based on ordinary arc spraying technology by improving the arc spray gun and power supply. It not only has the main characteristics of ordinary arc spraying technology, but also because of the increase in spraying speed, reaching and exceeding the speed of sound, so that the quality of the coating is significantly improved, the bonding strength is significantly improved, the porosity is greatly reduced, and the surface protection of wear-resistant and corrosion-resistant. In the field of surface treatment, the application prospects are significantly better than those of ordinary arc spraying.

3) Plasma spraying

Thermal spraying with plasma arc as the heat source. Its characteristics: no deformation of parts, many kinds of coatings, and stable process.

4. Laser surface modification technology

1) Laser phase change hardening: The surface layer of the iron-carbon alloy material is rapidly heated and austenitized by laser irradiation, while the matrix remains cooled; after the beam is removed, the austenite region depends on the rapid cooling of the matrix, Realize quenching, obtain martensite, and achieve the purpose of surface hardening.

2) Laser melting and hardening (laser grain refinement): Using higher laser energy than during phase change hardening, the metal surface is melted quickly and causes a large temperature gradient between the molten metal and the base metal. After the laser is removed, the molten metal solidifies rapidly, and the surface obtains an extremely fine or ultra-fine structure, the segregation of surface components is reduced, and the defects and micro-cracks on the surface can be fused. Laser melting can form a deeper hardened layer.

5. Electroless plating technology

In the case of no electricity, directly immerse the metal or non-metal workpiece in the chemical deposition solution below 100 ℃, and reflect on the surface of the workpiece through catalytic oxidation and reduction to obtain a new technology of amorphous alloy.

6. Functionally graded material (FGM) technology

A new material in which the microscopic composition and performance of the material changes gradually with the position and state of the material. That is, the two incompatible materials are merged into one through a gradient transition.

The preparation methods are mainly: deposition method, spraying method, sintering method, self-propagating high-temperature synthesis method, infiltration method, etc.

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