Surface treatment method of piston for quartering hammer

Abstract

The invention discloses a surface treatment method of a piston for a quartering hammer, which comprises the following steps: raw materials are forged and pressed to form a bar stock for the piston andthen isothermal annealing is conducted; rough treatment is conducted on a plain lathe and finishing allowance of 2mm is left on a circumferential surface and a scope of attack; the piston is carburized to lead the depth of a carburized layer to be up to 3mm; the circumferential surface of the piston is cut by 1.5mm on a numerically controlled lathe and the scope of attack thereof is cut by 2mm for fine treatment; the piston is quenched and tempered; and the circumferential surface of the piston is grinded, and the like. The surface treatment method of the piston for the quartering hammer firstly utilizes carbonization and then machining, and uses a more removal of the scope of attack to cause the scope of attack to become a low-carbon martensite, thereby enhancing the surface hardness ofthe scope of attack so as to be capable of improving the shock resistance of the scope of attack. In addition, the method for firstly conducting carbonization and then machining and finally quenchingis adopted to reduce the deformation of the piston, thus being capable of greatly reducing the stock removal, and increasing the qualification rate of products.

Description

technical field [0001] The invention relates to a piston for a breaking hammer, in particular to a surface treatment method for a piston for a breaking hammer. Background technique [0002] Breaking hammer is a kind of hydraulic energy as power to drive the piston inside the upper cylinder of the hydraulic cylinder to reciprocate, and hammer the drill rod through the piston to transmit energy to the drill rod, and the energy on the drill rod is then It is an important construction machinery that is absorbed by the hit object and crushed by the hit object. It is mainly used for crushing, demolition, and excavation of hard layers in construction. It is usually installed on excavators, loaders or power stations. It has the advantages of strong impact, convenient use, good maneuverability and high efficiency. figure 1 It is a structural schematic diagram of a hydraulic cylinder for a breaking hammer in the prior art. Such as figure 1 As shown, this prior art hydraulic cylinde...

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Problems solved by technology

But, there is following problem in the piston surface treatment method of above-mentioned this prior art breaker: because piston is to carry out carburizing treatment again through machining first, so the carbon content of the surface of piston 12 after carburizing treatment is 0.8-1.0% After quenching, the surface structure of the entire piston 12 is high-carbon martensite, which has high wear resistance, but is relatively brittle, low in toughness, and poor in impact resistance. Brittle spalling occurs, causing the piston to fail and be scrapped

In addition, since the length-to-diameter ratio of the piston 12 is generally about 4-5, and the above-mentioned surface treatment method will superimpose deformation after two times of quenching, so the grinding allowance is large, and it is easy to cause insufficient grinding due to large deformation. out, resulting in a higher workpiece scrap rate

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