RU2309987C2 - Method for making working organs of cultivators - Google Patents

Abstract

FIELD: machine engineering, namely manufacture of soil tilling machines such as cultivators.

SUBSTANCE: in order to improve wear resistance of working organs of tilling cultivators made of steel 60C2A, after imparting desired shape to working organ subjecting it to preliminary heat treatment at hardness 40 - 48 HRC; then surfacing stripes onto working surface of working organ by means of electrode and performing chemical-and-heat treatment by means of nitrogen for providing hardness of working surface 55 - 62 HRC. Invention provides increased by 1.5 times wear resistance of working surface of working organ.

EFFECT: improved wear resistance of working organ.

1 ex, 2 dwg

Description

The invention relates to technological processes in the field of mechanical engineering, namely to the manufacture of working bodies (ploughshare, coulter, lancet paws, etc.) for tillage cultivating machines.

Known methods for the manufacture of working bodies: authors Ivanov I.S. and other Agricultural Machines, Moscow, Mashinostroenie publishing house, 1970

Page 21. The paws of the subsoiler (lancet paws) are made of 65G steel, the cutting edges are heat treated HB 350-500 (HRC 38-51).

Page 23. Knife disks are made of 65G steel. Edges are heat treated HB 320-430 (HRC 35-45).

The blanks are cut to the required dimensions, molded into the required shape at the required angle by flexible forging or stamping, surfacing on the working surface of the wear-resistant material is done, and they are heat treated. This technology has the disadvantage of low wear resistance of the working bodies in the process of tillage. The resistance of the working bodies is 20 ha per working body.

The proposed method according to the invention provides increased wear resistance and is 30 hectares per working body, see the conclusion of the Chelyabinsk Agro-Industrial University.

Increasing the wear resistance of the working bodies is achieved due to complex heat treatment in the manufacturing process of the working body (Figs. 1 and 2): before surfacing, preliminary heat treatment of the working body for hardness 30-40 HRC is carried out, and after surfacing, it is chemically treated with nitrogen until hardness is obtained on the working surface 55-62 HRC, while 60C2A steel is used as the material for the manufacture of working bodies.

A method of manufacturing the working bodies of cultivators is carried out according to the following process.

1. Cutting blanks of the required geometry.

2. The shape of the workpiece in the desired geometric shape by flexible stamping, if necessary, machining.

3. Preliminary heat treatment in a shaft electric furnace with tempering at a hardness of 30-40 HRC to create the optimal metal structure for chemical-thermal treatment.

Hardening: parts neatly fit into specials. basket and placed in an oven, temperature 840 ° -870 ° С, holding time 1.3 min per 1 mm section;

- at the end of the exposure, cooling in oil t ° = 30 ° -70 ° C,

- hardness measurement to determine a more accurate tempering temperature.

Vacation: shaft electric furnace, temperature 450 ° -500 ° C, exposure at the rate of 2-3 min per 1 mm section, air cooling;

- sandblasting;

- OTC control - compliance with the temperature regime according to the diagram, hardness measurement 30-40 HRC.

4. Working edge surfacing:

- smooth the surface before surfacing to a metallic luster;

- calcine the E-500T or E-350T electrodes in a furnace at a temperature according to the label or GOST for a specific electrode, welding is performed by an electric welding current of 180-220 A for an electrode ⌀4 mm, 230-270 A for an electrode ⌀5 mm, surfacing is carried out by rollers 2.5-3.5 mm high, followed by removal of slag before applying the second layer.

No more than two layers are applied.

After surfacing, the working body (part) is placed in a furnace with t = 550 ° -600 ° C followed by cooling of the part and furnace to relieve internal stresses and eliminate cracks in the deposited layer.

5. Chemical-thermal treatment:

- The working surface, opposite to the deposited layer, is processed (polished) with a roughness ^Rα √ ^1.65 (according to the seventh class of cleanliness), blunt edges dull with a radius of at least 0.5 mm. To determine the depth of the nitrided layer, a sample is made. Chemical-thermal treatment with nitrogen is carried out in a special container, in a special electric furnace with a working space size of 1300 mm and a depth of 690 mm. Nitriding is carried out at t = 480 ° -500 ° C and is maintained for 8-10 hours. Nitrogen saturation is carried out in an atmosphere of dissociated ammonia with a degree of dissociation of 15-35% and an overpressure in a container of 60-120 mm water column. Hardness of nitrided work surface 55-62 HRC.

OTC control - compliance with the temperature regime according to the diagram, hardness measurement.

Claims (1)

A method of manufacturing the working bodies of cultivators, including cutting the workpiece, molding the necessary shape, surfacing on the working surface of a wear-resistant material and heat treatment, characterized in that prior to surfacing, the preliminary working heat treatment of the working body for a hardness of 30-40 HRc, and after surfacing - chemical-thermal treatment with nitrogen until a hardness of 55-62 HRc is obtained on the working surface, steel 60C2 is used as the material for the manufacture of the working bodies.

Images