CN1072727A

CN1072727A - The heat treating method of medium carbon manganese steel and low carbon manganese steel finished product

Info

Publication number: CN1072727A
Application number: CN 91111152
Authority: CN
Inventors: 王晶华
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-11-25
Filing date: 1991-11-25
Publication date: 1993-06-02
Anticipated expiration: 2006-11-25
Also published as: CN1027653C

Abstract

The present invention relates to a kind of to steel alloy 40Mn ₂And 20Mn ₂The heat treating method of finished product is specially adapted to using 40Mn ₂And 20Mn ₂The thermal treatment of the Off-the-road tire protection chain of making.In order to improve the wear resistance of Off-the-road tire protection chain, will use 40Mn ₂Rolling ring of making and same 20Mn ₂The Off-the-road tire protection chain that the shack of making is formed is heated to 820～850 ℃; be incubated to put into after 1～1.5 hour and contain 0.2～0.3% polyvinyl alcohol water solution and be quenched to below 100 ℃ with the speed of 37～50 ℃/sec; be heated to 360～380 ℃ again; be incubated after 2 hours, in air, be cooled to room temperature.This treatment process makes rolling ring hardness reach HRC45～50, and shack reaches HRC35～40, and does not crack, and reach more than 1 year its work-ing life.

Description

The heat treating method of medium carbon manganese steel and low carbon manganese steel finished product

The present invention relates to a kind of to steel alloy 40Mn ₂With the heat treating method of 20Mn finished product, be particularly useful for using 40Mn ₂Pass through section rolling ring of making and use 20Mn ₂The thermal treatment of the Off-the-road tire protection chain that the shack of process welding is made.

Wheel loader and transport trolley in engineering constructions such as waterpower, electric power, mining, railroad constructions, they often are operated in behind rubble or the rock etc. on the abominable ground of environment, make tire wear and scratch very serious, only work sometimes tens days will re-type, this is very big waste.For a long time, people find out the work-ing life that a lot of ways prolong its tire.Wherein on tire, enclose a metal protection chain to increase the working life of tire.The beginning people make the protection chain with carbon steel.With the protection chain that soft steel is made, because wear resistance is lower, though than protecting increase the work-ing life of chain, the life-span is not long, and this manufacturing expense of protecting chain is than higher, from economic angle and be not worthwhile; If make, because the shack of protection chain needs welding of the carbon steel that carbon content is high.Because of the carbon content height, weldability is reduced, often, its shack cracking becomes waste product because of making the protection chain; If with the good medium carbon alloy steel of wear resistance, as 40Mn ₂Make rolling ring through forging, with weldability good low-carbon alloy steel such as 20Mn ₂Make shack, again they are combined into tire protection chain, this protection chain is owing to be two kinds of material manufacturings, and its thermal treatment difficulty is very big; Use water as quenching medium, 20Mn ₂Shack can reach the hardness of HRC35～40, still, use 40Mn ₂The rolling ring of making is but because carbon content is higher, because too fast the cracking of quenching velocity becomes waste product; If make quenching medium with oil, 40Mn ₂Rolling ring can reach the hardness of HRC＞50, but use 20Mn ₂The hardness of the shack of making does not but reach HRC30.

The objective of the invention is to using steel alloy 40Mn ₂And 20Mn ₂Finished product a kind of heat treating method is provided, make it use 40Mn ₂The hardness of the part of making is used 20Mn between HRC45～50 ₂The hardness of the part of making is between HRC35～40, and these two parts can not crack.

Between 340, and these two parts can not crack.

The present invention can realize by following measure:

To use 40Mn ₂Medium carbon alloy steel part and use 20Mn ₂The finished product of low-carbon alloy steel part are placed on and are heated to 820～850 ℃ in the process furnace, are incubated after 1-1.5 hour, put into to contain 0.2～0.3% polyvinyl alcohol water solution and be cooled to below 100 ℃ with the speed of 40～60 ℃/sec.The quenching characteristics that contains 0.2～0.3% polyvinyl alcohol water solution is between water and oil, and it can prevent medium carbon alloy steel 40Mn ₂Too fast in the martensite transformation temperature of C-curve when quenching, cause the excessive crackle that occurs of internal stress; Can not look like 20Mn again ₂Low-carbon alloy steel at the too for a short time quenched martensite that can not get of C-curve nose speed of cooling, and makes hardness low excessively when oil quenching.Why the Heating temperature of quenching is selected in 820～850 ℃, is because 40Mn ₂AC ₃Point is 770 ℃, 20Mn ₂AC ₃Point is 840 ℃.As be lower than 820 ℃, though to 40Mn ₂Influence little, but to 20Mn ₂Owing to be lower than AC ₃Point has ferrite and exists and the reduction quenching hardness; If quenching temperature is higher than 850 ℃, though to 20Mn ₂Be suitable, but surpass 40Mn ₂AC ₃Put more than 80 ℃, like this austenite crystal is grown up, its result causes quenching crack easily.Because manganese steel is at the austenite transformation temperature austenite crystal steel grade of growing up easily therebetween, so soaking time can not be above 1.5 hours.

Through the 40Mn after quenching ₂And 20Mn ₂Finished product are put into stove again and are heated to 360-380 ℃, are incubated and promptly come out of the stove cool to room temperature in air after 2 hours.This tempered purpose is to eliminate the internal stress that produces when quenching, and obtains the tempered troostite tissue, thereby keeps 20Mn ₂Hardness reach HRC35-40, and make it be organized as troostite; 40Mn ₂Hardness reach HRC45～50.

The present invention can also realize by following measure:

At 40Mn ₂And 20Mn ₂Finished product are put into stove and are heated to 840～860 ℃ before quenching, and being incubated came out of the stove after 2 hours is cooled to room temperature in air.The purpose of this normalizing be to eliminate two kinds of steel alloys when forming finished product because hot-work institute

The present invention compared with prior art has following advantage:

1, contains 0.2～0.3% polyvinyl alcohol water solution quenching medium and can make 40Mn ₂And 20Mn ₂The hardness of finished product reaches HRC45～50 and HRC35～40 respectively;

2, it is low to contain 0.2～0.3% polyvinyl alcohol water solution price, preparation easily, and safe in utilization, not on fire also the generation splashed, and be free from environmental pollution, and the surface blackening that quenching medium is handled plays rust inhibition;

3, with containing the 40Mn that 0.2～0.3% polyvinyl alcohol water solution is handled ₂And 20Mn ₂Finished product can not crack;

4, this heat treating method makes the 40Mn of processing ₂And 20Mn ₂The long service life of finished product, can reach more than 1 year under the same conditions and use group to order with the engineering truck protection chain that the present invention handles the maximum half a year in work-ing life as after the engineering truck protection chain warp quenching made from soft steel.

Description of drawings is as follows:

Fig. 1 is steel alloy 40Mn of the present invention ₂And 20Mn ₂Temperature-time changing curve when finished product quench;

Fig. 2 is steel alloy 40Mn of the present invention ₂And 20Mn ₂Tempered temperature-time changing curve after finished product quench;

Fig. 3 is steel alloy 40Mn of the present invention ₂And 20Mn ₂Temperature-time changing curve that finished product carry out normalizing before quenching;

Fig. 4 is for using steel alloy 40Mn ₂And 20Mn ₂Through forged rolling ring and steel alloy 20Mn ₂A kind of local structure synoptic diagram of the Off-the-road tire protection chain that the shack through welding is formed;

Fig. 5 is for using steel alloy 40Mn ₂And 20Mn ₂The metallograph of the rolling ring of the engineering truck protection chain of making after the thermal treatment of the present invention;

Fig. 6 is for using steel alloy 40Mn ₂And 20Mn ₂The metallograph of the shack of the engineering truck protection chain of making after the thermal treatment of the present invention.

The metallograph of shack after the thermal treatment of the present invention.

Now the invention will be further described in conjunction with the accompanying drawings:

Among Fig. 41 is for using 40Mn ₂Forged rolling ring, 2 for using 20Mn ₂Forge circlewise and after being enclosed within on the rolling ring 1 and again the opening of shack is welded the shack that extremely forms.Several rolling rings and shack are made up of an Off-the-road tire protection of three monolithics (every 100 kilograms) formation chain.To protect the chain monolithic to put into box resistance heading furnace and be heated to 840～860 ℃, be incubated after 2 hours, from stove, take out, in air, be cooled to empty temperature; To protect again the chain monolithic put into stove be heated to 820～850 ℃ and be incubated 1-1.5 hour after, put into and contain 0.2～0.3% polyvinyl alcohol water solution and be quenched under 100 ℃ with the speed of 40～60 ℃/sec; To protect the chain monolithic to put into stove again and be heated to 360～380 ℃, be incubated after 2 hours, in air, be cooled to room temperature.With this method heat-treat make the protection chain rolling ring hardness reach HRC45～50, the hardness of shack reaches HRC35～40.

Claims

1, the heat treating method of a kind of steel alloy 40Mn2 and 20Mn2 finished product; Be specially adapted to the rolling ring made by 40Mn2 steel alloy section and with of the thermal treatment of 20Mn2 steel alloy, it is characterized in that through the made Off-the-road tire protection chain of the shack of welding:

(1) makes quenching medium by the polyvinyl alcohol water solution that contains 0.2～0.3%;

(2) steel alloy 40Mn2 and 20Mn2 finished product are heated to 820 °～850 °, are incubated after 1-1.5 hour, put into 0.2～0.3% polyvinyl alcohol water solution with the speed of 37-50 ℃/sec and be cooled to below 100 ℃;

(3) steel alloy 40Mn2 and 20Mn2 finished product are heated to 360～380 ℃, are incubated after 2 hours, in air, be cooled to room temperature.

2, steel alloy 40Mn according to claim 1 ₂And 20Mn ₂The heat treating method of finished product is characterized in that: before quench treatment, be heated to 840～860 ℃, be incubated after 2 hours, be cooled to room temperature in air.