PL232515B1 - Method for manufacturing or upgrading the wear resistant layers - Google Patents

Description

Description of the invention

The subject of the invention is a method of producing or refining wear-resistant layers, especially on the working surfaces of machine parts and tools that are simultaneously exposed to dynamic loads, such as, for example, hammer crushers, impact crushers, conical crushers, jaw crushers and roller crushers, punching dies or dies.

The methods of shaping and increasing the tribological properties of the working surfaces of machine parts and tools, usually made of tool steels, known and used so far, mainly consist in the use of heat or thermo-chemical treatment, which leads to a significant increase in hardness. There are also methods consisting in applying top layers of metals and metal alloys of high hardness by means of mainly arc deposition technology, such as those known from the Polish patent specification No. P 153830 and P 198494, thermal spraying or other methods of applying coatings, as known from Polish patent description No. 214615 and 213 917 methods of applying special electroplating coatings, but of small thickness. The high-hardness working surface layers produced in this way provide significant resistance to abrasive wear, but only under static or moderate dynamic load conditions, as usually an increase in the hardness of a metal or metal alloy is associated with a simultaneous reduction in its plastic properties and toughness. Another way to ensure high tool service life is to use tungsten carbide tips, which have a high hardness. However, when parts are exposed to intense dynamic (i.e. impact) loads at the same time, the high-hardness surface layers crack and then chip, which in turn significantly reduces the effective service life or even leads to sudden failure of such parts and failure of the entire device or machine. There are also known from the Chinese patents CN103194748 and CN103484852 methods of producing composite layers by means of laser deposition, but their essence consists in the use of a prepared and mixed composite powder with specific proportions, and the matrix is a powder based on nickel and chromium. These patents, due to the operational properties of the surface layers and the scope of patent protection, apply only to surfacing of the heads of drilling tools used in the petroleum industry and intended for making deep wells.

The method of producing or refining wear-resistant layers according to the invention by laser surfacing in an argon shield is based on the fact that the surface is melted with a laser beam with a power of 1.5: 2.5 kW at a laser beam speed of 0.3: 5 m / min, and the weld pool is fed simultaneously but separately with iron-based metallic powder with addition of 0.9: 1.1% C, 11: 12.0% Mn and 0.3: 45 Si at a powder feed rate of 4.0: 9 0.0 g / min and spheroidal tungsten carbide powder with a grain size of 80: 250 gm, at a powder feed rate of 5.0: 15 g / min.

The surface is melted with a laser beam at a depth not exceeding 0.3 mm.

The described method enables the production of a composite layer with special operational properties, which has high abrasion resistance provided by tungsten carbides with high hardness, and at the same time high resistance to dynamic loads thanks to a metal matrix with high plasticity and a hardness of approx. 250 HB after laser welding, which additionally, it tends to strengthen as a result of loading and dynamic deformation. The size and form of tungsten carbides (spheroidal) guarantee their minimal melting in the surfacing process, perfect metallurgical connection with the matrix and favorable distribution of stresses, especially at the carbide-matrix interface. The deposition method according to the invention enables the production of outer layers with a thickness of 0.5 to 4.0 mm.

The method according to the invention has been presented in an exemplary embodiment.

In order to make a crusher hammer on the working surface with a body made of S355J2G3 steel and a cross-sectional thickness of 15.0 mm of a wear-resistant surface layer, surfacing with a laser beam with a focus diameter of 3.0 mm, power of 1.8 kW and speed of 300 mm / min was carried out. to the weld pool simultaneously metallic powder based on iron Fe with the addition of 0.9% C, 11.5% Mn and 0.35 Si at a feeding rate of 4.0 g / min and tungsten carbide powder with a feeding rate of 5.5 g / min and grain size 150: 200 gm. The surfacing was carried out in multiple runs and in multiple layers in order to cover the entire working surface of the hammer with a padding weld with a thickness of 2.5: 3.0 mm.

Claims (2)

Patent claims 1. The method of producing or refining wear-resistant layers by laser surfacing in an argon shield, characterized by the fact that the surface is melted with a laser beam of 1.5: 2.5 kW power at a laser beam speed of 0.3: 5 m / min , and the weld pool is fed simultaneously but separately with iron-based metal powder with 0.9: 1.1% C, 11.0: 12.0% Mn and 0.3: 0.45 Si at the powder feed rate 4.0: 9.0 g / min and spheroidal tungsten carbide powder with a grain size of 80: 250 μm at a powder feed rate of 5.0: 15 g / min. 2. The method according to p. The method of claim 1, characterized in that the surface is melted with the laser beam at a depth not greater than 0.3 mm.