CN101967542A

CN101967542A - Toughness process method of 42CrMo material

Info

Publication number: CN101967542A
Application number: CN 201010543894
Authority: CN
Inventors: 康建峰; 邝胜海
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-11-15
Filing date: 2010-11-15
Publication date: 2011-02-09

Abstract

The invention discloses a toughness process method of 42CrMo material, comprising the following steps of: heating the material to completely austenitize the material; then reducing the temperature to precipitate ferrolite to form an ausferrite; and quenching and tempering the ausferrite. The invention has the following advantages: the method can improve the intensity index and the toughness index of the 42CrMo material at the same time, and parts manufactured through the material can work normally for a long time in bad weather.

Description

The strengthening and toughening treatment method of 42CrMo material

Technical field

The present invention relates to a kind of thermal treatment process, relate in particular to a kind of strengthening and toughening treatment method of 42CrMo material.

Background technology

Wind-powered electricity generation is the important component part of clean energy, but the wind-powered electricity generation unit all is in the abominable place of open-air natural condition, and stressing conditions is complicated and changeable, and this has just proposed very harsh requirement to the reliability of the joint bolt on the unit; The intensity index of joint bolt (tensile strength) will reach σ _b1100MP _αMore than, surpass the σ that GB GB/T3098.1 stipulates _b1040MP _αRequirement; Simultaneously, if make blower fan works better under the north of china in winter severe cold weather, the toughness index of its joint bolt need reach-40 ℃ more than the low-temperature impact work Akv35J, and this is also more harsh than the requirement of the normal temperature ballistic work Akv27J of GB regulation.

For the 42CrMo material, because intensity index and toughness index are contradiction each other,, improve one of them index if adopt common heat treatment quenching and tempering technology, to cause another index to descend, common heat treatment quenching and tempering technology can not satisfy the requirement of intensity index and toughness index simultaneously; At the problem that two kinds of indexs can not be taken into account, prior art can only solve by selecting the very expensive Ni material (as 40CrNiMo) that contains for use, and this makes production cost significantly increase.

Summary of the invention

At the problem of describing in the background technology, the present invention improves the treatment process of material on the basis that does not change the 42CrMo material, the intensity index of 42CrMo material and toughness index is all reached make the blower fan requirement used of mal-condition in the open air; Concrete treatment step is: 1) the 42CrMo material is heated above 60 ℃ ~ 80 ℃ of the austenitizing temperature Ac3 of 42CrMo material, and under this temperature the 42CrMo material is incubated, soaking time satisfies makes the complete austenitizing of 42CrMo material;

2) to the 42CrMo material after handling through step 1), be lower than in temperature under the condition of 5 ℃ ~ 10 ℃ of austenitizing temperature Ac3, the 42CrMo material is incubated, soaking time satisfies makes the ferrite in the 42CrMo material separate out content 5% ~ 10%;

3) to through step 2) 42CrMo material after handling quenches;

4) to the 42CrMo material after handling through step 3), carry out temper, the unrelieved stress after the elimination quench treatment.

Soaking time is more than 2 hours in the described step 1) of preamble.

The described step 2 of preamble) soaking time is more than 2 hours in.

Temper in the described step 3) of preamble comprises: under 530 ℃ of conditions of temperature, to 42CrMo material insulation 3 hours.

Useful technique effect of the present invention is: adopt the inventive method, can make cheaply that the intensity index and the toughness index of 42CrMo material are improved simultaneously, the produced part of material can satisfy the long-term in bad weather conditions works better of equipment thus.

Description of drawings

Fig. 1, process flow diagram of the present invention;

Fig. 2, handle the 42CrMo material metallograph obtain through ordinary process;

Fig. 3, employing technology of the present invention after the two-phase region quenches, are carried out the 42CrMo material metallograph after low-temperaturetempering is handled;

Fig. 4, the 42CrMo material metallograph that adopts technology of the present invention to obtain.

Embodiment

In the steel internal organizational structure, ferrite is soft and tough, and martensite is hard and crisp, the incompatibility of two kinds of tissues, but utilize the dual phase steel principle, as long as make the metallographic of two kinds of tissues reasonably combined, be to obtain higher intensity and flexible simultaneously; Specifically, be exactly in heat treatment process, the parameter (temperature and time) of control thermal treatment process, reach adjustment ferrite and martensite (more precisely, should be to transform the tempered sorbite obtain by martensite) the purpose of quantity, pattern and distribution characteristics, so just can solve the contradiction between intensity and the toughness, final acquisition possesses higher-strength and flexible material simultaneously.

Thinking of the present invention is: allow the metallographic structure of material internal all be converted into austenite, and then make it separate out the part ferrite, form duplex structure, and quench in the two-phase region, make remaining austenite (promptly separate out ferrite after remaining austenite) form quenched martensite, again material is carried out tempering, make quenched martensite be converted into tempered sorbite, finally obtain the novel material that structure is made up of tempered sorbite and ferrite; Its concrete steps are:

1) the 42CrMo material is heated above 60 ℃ ~ 80 ℃ of the austenitizing temperature Ac3 of 42CrMo material, and under this temperature the 42CrMo material is incubated, soaking time satisfies makes the complete austenitizing of 42CrMo material;

3) to through step 2) 42CrMo material after handling quenches;

This wherein has several problem values to illustrate:

At first, in the austenite conversion process in step 1), austenitizing temperature Ac3(is for the 42CrMo material, its austenitizing temperature Ac3 is 780 ℃) only be a stagnation point, only heat temperature so far, can't guarantee the abundant, complete of material austenitizing, so temperature need be increased to more than the austenitizing temperature Ac3; But, this temperature again can not be too high, the too high meeting of temperature causes the austenitic crystal grain that obtains comparatively thick, influence the character of material, the contriver is through studying for a long period of time, discovery has only it is controlled in 60 ℃ ~ 80 ℃ scopes, could both guarantee that the austenitizing of material carried out fully efficiently, is unlikely to make the austenitic crystal grain that obtains comparatively thick again.In the step 1), behind 60 ℃ ~ 80 ℃ of the austenitizing temperature Ac3 that the 42CrMo material is heated above the 42CrMo material, also to be incubated material, its soaking time also has very big difference with prior art, in the prior art, in order to save the energy, detect by experiment generally that the material complete austenitizing is needed guarantees the minimum the time, consider from the angle of saving the energy then, shorten its soaking time as far as possible, but the contriver thinks that this thinking is incorrect, adopts the soaking time of guaranteeing the minimum, though austenite is transformed fully, also no doubt saved the energy, but this can make the austenite crystal of gained inhomogeneous, and even for the austenite crystal that makes gained, the contriver thinks and holding temperature should be arranged on more than 2 hours.

About step 2), existing theory is thought, ferritic content should be controlled in zone of reasonableness, otherwise the structure to material is harmful, but do not have concrete technology and instruct the ferrite that how to obtain zone of reasonableness, the contriver is by a large amount of research, discovery is controlled at temperature under the condition that is lower than 5 ℃ ~ 10 ℃ of austenitizing temperature Ac3, it is low more in 5% ~ 10%(temperature to make ferrite separate out stable content, it is many relatively more that ferrite is separated out content) because the real material property of there are differences, as long as guarantee step 2) in soaking time more than 2 hours, the ferrite content that just can guarantee to separate out and is evenly distributed in 5% ~ 10% scope.

About step 3), after the quench treatment, austenite in the material is converted into quenched martensite in quenching process, in temper through step 4), quenched martensite is converted into tempered sorbite, in this process, important is tempered temperature and tempering time, temper can be eliminated the unrelieved stress of the material internal that causes because of quench treatment, tempering temperature is relevant with the material hardness HRC of resulting product, the contriver is through discovering, to the 42CrMo material of standard quality, tempering process is controlled at 530 ℃ of temperature, under 3 hours the condition of tempering time, the material hardness HRC that can make product is 37 ± 1, and the intensity index (tensile strength) that satisfies material reaches σ _b1100MP _αMore than.Tempering temperature and time can be adjusted according to the material difference of actual product, and in general tempering temperature is high more, and material hardness HRC is low relatively more,

Referring to Fig. 2, by the resulting 42CrMo material of ordinary process, its crystal grain part is thick, and each metallographic structure skewness; Referring to Fig. 4, by the resulting 42CrMo material of technology of the present invention, it is examined covering weave is that equally distributed tempered sorbite is organized, and its crystal grain is tiny, and each metallographic structure is evenly distributed; Referring to Fig. 3, can be differentiated by naked eyes at microscopically in order to make ferrite, the metallograph that obtains after adopting low-temperaturetempering (200 ℃ ~ 300 ℃) to handle, as can be seen from the figure, being examined covering weave is that equally distributed tempered martensite+a little ferrite is organized, ferrite is evenly distributed, and quantity is about 8%.Fig. 3 and Fig. 4 are the two-phase region that adopts technology of the present invention and quench, and the 42CrMo material metallograph that only tempering temperature is different, the ferrite among Fig. 4 distribute similar to the ferrite distribution among Fig. 3.

Claims

1. the strengthening and toughening treatment method of a 42CrMo material, it is characterized in that: its processing step is: 60 ℃ ~ 80 ℃ of austenitizing temperature Ac3 that 1) the 42CrMo material are heated above the 42CrMo material, and under this temperature, the 42CrMo material is incubated, soaking time satisfies makes the complete austenitizing of 42CrMo material;

3) to through step 2) 42CrMo material after handling quenches;

2. the strengthening and toughening treatment method of 42CrMo material according to claim 1 is characterized in that: soaking time is more than 2 hours in the step 1).

3. the strengthening and toughening treatment method of 42CrMo material according to claim 1 is characterized in that: step 2) in soaking time be more than 2 hours.

4. the strengthening and toughening treatment method of 42CrMo material according to claim 1 is characterized in that: the temper in the step 3) comprises: under 530 ℃ of conditions of temperature, to 42CrMo material insulation 3 hours.