CN1186896A

CN1186896A - High hardness high toughness pick and preparing technology

Info

Publication number: CN1186896A
Application number: CN96118953A
Authority: CN
Inventors: 蔡正斌; 丁建础
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-12-29
Filing date: 1996-12-29
Publication date: 1998-07-08

Abstract

The characteristic lies in that the tooth body of the pick is formed by once casting the double phase medium carbon low-alloy steel, the head of the pick is a wear resistance layer overlaid directly by using high hardness alloy wear overlaying electrode. The invented pick possesses of good mechanical properties, the hardness of the pick body HRC/54, the toughness is 685/cm sq., the hardness of the head of the pick HRC can come up to 62 odd, the life is double of the pick produced by available method. Besides, the resources of the raw material is intersive, the preparative process is simple and the cost can lower by 20% odd.

Description

High-intensity high-tenacity pick and preparation technology

The invention belongs to field of metallurgy.

The present invention be more particularly directed to a kind of high strength, high toughness pick and preparation technology thereof.

Pick is mounted in the main parts that directly cut the coal seam on the coal mining machine roller and finish the coal mining function, raising along with the Mechanized Coal Mining Operation in China degree, pick consumption in coal mining increases day by day, and the quality of pick performance directly affects the utilization rate and the coal mining efficient of coal-winning machine.At present, both at home and abroad its architectural feature of pick of producing is: pick by the pick body (accompanying drawing 1, a) and garden cylindricality carbide alloy (accompanying drawing 1, the b) two parts of inserting form, its pick end of body is installed on the coal mining machine roller in the pick box, and carbide alloy is inserted and is welded on the head of pick body.Different its concrete shape and size of pick model are also slightly different.

At present, the technology of producing pick both at home and abroad is: pick denticle blank is produced in (1) die forging; (2) the pick body is heat-treated; (3) boring, plane mill and shaping; (4) carbide alloy is inserted be welded in the pick body head bore; (5) finishing and processing.

Adopt the pick of said method production that following problems is arranged: (1) is hit brittle fracture easily takes place because carbide alloy is inserted firmly and crisply; (2) because the copper brazing bond strength is low, carbide alloy is inserted and is easily separated with the pick body; (3) denticle employing die forging need be dug and be milled, and (some model needs 2 holes) production technology of also will holing is complicated; (4) denticle poor impact toughness, hardness is low fragile.

Problem at above-mentioned existence, 89101285 pairs of existing pick production technologies of Chinese patent are improved, the pick denticle adopts die forging or cast iron, bore several diameters 5-10mm boring at pick body head, adopt iron-based, Ni-based or cobalt base self-fluxing alloy powder, spraying high-hard antiwear coating, increase the scuff resistance of pick, prolonged the application life of pick.But the pick of this technology manufacturing still exists the intensity of following point (1) pick denticle own, toughness lower, and needs boring, digs to mill etc., and technology is still continued to use present method both domestic and external, and the material therefor price is higher; (2) need to bore several diameters 5-10mm boring before the powder spraying, and will give heat, temperature is difficult for grasping difficult quality guarantee, and complex process during spraying.

The object of the present invention is to provide a kind of manufacturing process simple, the raw material wide material sources, performance is better than high strength, the high toughness pick of Chinese patent 89101285.

Task of the present invention realizes with following technique process:

1, adopts two-phase medium carbon low alloy steel casting pick denticle a ";

2, at the wear-resisting layer b of pick body head built-up welding high hardness alloy ";

3, trimming processing;

4, heat treatment;

The invention will be further described below in conjunction with accompanying drawing, wherein Fig. 1 is the tabular pick structural representation that the domestic and international at present technology that generally adopts is produced, Fig. 2 is the pick structural representation that Chinese patent 89101285 technology are produced, and Fig. 3 is a pick structural representation of the present invention.

As shown in Figure 1, the pick that traditional handicraft is produced is made of pick body a and the carbide alloy b two parts of inserting, since carbide alloy insert and pick body a between be inserted soldering combination, therefore easily produce stress and concentrate in pick body c district, this stress is concentrated the sealing-off and the fragmentation that can cause carbide alloy to be inserted.

As shown in Figure 2, this pick comprises pick denticle a ' and wear-resistant coating b ', the spraying of wear-resistant coating b ' employing powder, and used spray material is iron-based, Ni-based or cobalt base self-fluxing alloy powder, the hardness of its spray-welding coating is HRC58.

High rigidity of the present invention, its structure of high toughness pick comprise pick denticle a " and high hardness alloy wearable overlay b " as shown in Figure 3.The 1st road technology pick denticle a of (the present invention) is " by the moulding of two-phase medium carbon low alloy steel one-step casting; its shape is different among Fig. 1 a ' among a and Fig. 2; head is taper, wedge shape or irregular shape with the inlaid hole of layer on every side; overall big outer little in becoming; so that layer combines firmly difficult drop-off with the pick body.The two-phase medium carbon low alloy steel is to add a small amount of alloying element melting to form in scrap steel, and its micro-addition is: C:0.38-0.45%, Mn:1-1.2%, Si:1.4-1.6%, Mo:0.3-0.5%, S:0.003%, P:0.04%.

The 2nd road technology of the present invention is to use electric welding machine or arc welder to adopt the direct built-up welding of high hardness alloy hardfacing bar in pick head and connecting hole, and layer b " combines very tight with denticle; " the thick 3-5mm of scope layer, length is 20mm to b.

The 3rd road technology of the present invention is meant simply rebuilds pick, so that the most advanced and sophisticated curvature that is is garden arcuation cutting edge about 15 degree.

The 4th road technology of the present invention is that whole pick is heat-treated, and process of thermal treatment is: isothermal spheroidizing, the air cooling mode is quenched, lonneal.

Whole pick hardness is big, toughness is high.Wherein the hardness HRC of denticle own can reach more than 54, and impact toughness can reach 68J/cm ², pick head hardness HRC can reach more than 62.Denticle is firm not fragile in the coal mining process, and the pick made of technology thus can be enhanced about more than once than the pick of traditional handicraft preparation through the on-the-spot experiment of mining repeatedly application life, and manufacturing cost can reduce more than 20%.

This technology can be processed recycling to using the old pick of scrapping, promptly forms at pick head built-up welding high hardness wear-resisting alloy-layer.

Pick of the present invention is compared with existing pick, has following advantages: (1) raw material wide material sources, and cheap; (2) production technology is simple, and cost is low, reduce more than 20% than traditional pick preparation technology and Chinese patent 89101285 technologies, and wearability, toughness all is better than present pick. Can be enhanced about more than once service life, and (3) denticle is reusable.

Claims

1, the preparation method of a kind of high rigidity, high toughness pick comprises: (1) preparation pick denticle a " (accompanying drawing 3); (2) " the wear-resisting layer of head built-up welding high hardness alloy at pick body a; (3) pick is heat-treated; (4) pick is rebuild processing.It is characterized in that said pick body a " is that said layer b " forms for the built-up welding of high hardness alloy wear resistance electrode by the moulding of two-phase medium carbon low alloy steel one-step casting.

2,, it is characterized in that said two-phase medium carbon low alloy steel is to add micro-melting to form in steel scrap according to the method for claim 1.The trace element composition is: C:0.38-0.45%, Mn:1-1.2%, Si:1.4-1.6%, M.：0.3-0.5％、V：0.02-0.14、S：0.003％、P：0.04％。

3, according to the method for claim 1, it is characterized in that said layer b and " be to use the high hardness alloy hardfacing electrode, realize with the technology of electric resistance welding, arc welding.

4, according to the method for claim 1, it is characterized in that said Technology for Heating Processing is an isothermal spheroidizing, the air cooling mode is quenched, lonneal technology.

5, according to the method for claim 1, the inlaid hole D that it is characterized in that said pick denticle head is interior big outer little.