CN106282804B - A kind of high abrasion high manganese cast steel of Cr Al Nb V alloys - Google Patents

Abstract

The invention relates to a Cr-Al-Nb-V alloyed high-wear-resistant high-manganese cast steel, the chemical composition of which is by weight percentage (wt.%): C: 1.20-1.60wt.%, Si: 0.25- 0.75wt.%, Mn: 16.0~20.0wt.%, Cr: 3.00~5.00wt.%, Al: 1.00~2.00wt.%, Nb: 0.04~0.10wt.%, V: 0.10~0.20wt.%, P<0.03wt.%, S<0.015wt.%, the balance is Fe and unavoidable impurities. According to the high manganese steel composition and mass percentage, the raw materials are mixed and placed in a vacuum induction heating furnace, fully melted and then kept for 8 to 10 minutes to make high manganese molten steel, and cast to form a casting after being released from the furnace. The heat treatment method of staged heating is adopted. First, the casting is heated to 750-850°C at a rate of 100-150°C/h and kept for 1-2 hours, and then the casting is heated to 1000-1200°C and kept for 1-2 hours. After 4 hours, it is finally taken out of the furnace and cooled to room temperature, and the impact and wear resistance obtained is more than 30-50% higher than that of ZG120Mn17Cr2. Due to the high content of corrosion-resistant alloy elements such as Cr and Al, its advantages in impact, wear and abrasion resistance are more obvious in a slightly corrosive environment.

Description

A Cr-Al-Nb-V alloyed high wear-resistant high manganese cast steel

technical field

The invention belongs to the field of wear-resistant cast steel, and in particular relates to Cr-Al-Nb-V alloyed high-wear-resistant high-manganese cast steel.

Background technique

Wear-resistant high-manganese steel Mn13 has a history of more than 100 years since its invention. The structure of the service state is austenite. Under the use state of large impact load or contact stress, the surface hardens rapidly and has excellent impact and wear resistance. . High-manganese austenitic steel is therefore difficult to deform and machine, and is often used in the form of cast steel. As the wear resistance requirements of high manganese austenitic cast steel are getting higher and higher under actual working conditions, the development of various improved high manganese steels has been paid attention to. Such as the successful application of improved high manganese steel ZG120Mn13Cr2, ZG120Mn17Cr2, due to the addition of about 2% (mass percentage) of Cr, the initial hardness and work hardening ability are improved, and the wear resistance is greatly improved compared with Mn13 high manganese steel; but An excessively high Cr content significantly reduces impact toughness. The use of Mo instead of Cr can also improve wear resistance, but because Mo is expensive, high manganese steels using Mo instead of Cr are rarely used. In addition, there are some studies or patents CN105803322A, CN105779889A such as adding Ti, W and other strong carbides to form a large number of coarse hard phases such as TiC, WC, etc. to increase hardness, but at the same time significantly reduce impact toughness, which is not conducive to Its impact and wear properties are improved. The invention discovers and utilizes the synergistic regulation and control effect of Cr-Al-Nb-V on high manganese austenite, develops a new type of high wear-resistant high manganese steel and its water toughening treatment process, and significantly improves the impact resistance of high manganese steel Abrasive.

Contents of the invention

The object of the present invention is to provide a Cr-Al-Nb-V alloyed high wear-resistant high manganese cast steel. In terms of chemical composition, through the idea of Al alloying, it breaks through the previous limit of Cr content, and at the same time adopts Nb-V composite microalloying to refine the austenite grain size, and jointly and significantly improves the impact resistance of high manganese steel Abrasive. In order to achieve the above-mentioned technical goals, the technical scheme of the present invention is specifically as follows:

A Cr-Al-Nb-V alloyed high wear-resistant high-manganese cast steel, chemical composition C: 1.20-1.60wt.%, Si: 0.25-0.75wt.%, Mn: 16.0-20.0wt.%, Cr : 3.00～5.00wt.%, Al: 1.00～2.00wt.%, Nb: 0.04～0.10wt.%, V: 0.10～0.20wt.%, P<0.03wt.%, S<0.015wt.%. Amounts are Fe and unavoidable impurities, all in weight percent.

Preferably, chemical composition C: 1.20-1.35wt.%, Si: 0.25-0.35wt.%, Mn: 16.0-18.0wt.%, Cr: 3.00-3.50wt.%, Al: 1.00-1.30wt.%, Nb: 0.04-0.07wt.%, V: 0.10-0.13wt.%, P<0.01wt.%, S<0.010wt.%, the balance is Fe and unavoidable impurities, all in weight percentage.

Preferably, the chemical composition C: 1.50-1.60wt.%, Si: 0.50-0.75wt.%, Mn: 18.5-20.0wt.%, Cr: 4.00-5.00wt.%, Al: 1.60-2.00wt.%, Nb: 0.08-0.10wt.%, V: 0.15-0.20wt.%, P<0.03wt.%, S<0.015wt.%, and the balance is Fe and unavoidable impurities, all in percent by weight.

Preferably, the total amount of Nb and V is not higher than 0.30wt.%.

Preferably, the Mn/C mass ratio is not lower than 10.

Preferably, the Al/Cr mass ratio is not lower than 1:5.

Preferably, the Nb/C mass ratio should be controlled to be 1:30-1:15, the V/C mass ratio should be controlled to be 1:12-1:8, and the V/Nb mass ratio should be controlled to be greater than 2.

Preferably, the carbide size of Cr in the steel is less than 5 microns, and the austenite grains are 50-100 microns.

Further, a method for preparing the above-mentioned Cr-Al-Nb-V alloyed high-wear-resistant high-manganese cast steel is provided, which is characterized in that raw materials are mixed according to the composition and mass percentage of high-manganese steel and put into vacuum induction heating In the furnace, it is fully melted and then kept warm for 8-10 minutes to make high-manganese molten steel. After it is released from the furnace, it is cast to form a casting. The heat treatment method is heated in sections. ℃ for 1 to 2 hours, then continue to heat the casting to 1000 ℃ to 1200 ℃ with the furnace heating and keep it for 1 to 4 hours, and finally take it out of the furnace and water cool it to room temperature.

The effect and proportioning basis of each element of the present invention are as follows:

Carbon: Higher C content is an important guarantee for the wear resistance of high manganese steel. Solid solution C in austenite can ensure the work hardening ability of high manganese austenite, and the precipitated C increases the hardness of high manganese steel. The present invention adopts the design principle of higher manganese content and Nb, V composite microalloy, the solid solution C content in austenite is not less than 1.10wt.%, and the total C content increases synchronously with the total amount of Nb and V. Excessive C content and the total amount of Nb and V are not conducive to the guarantee of impact toughness. Therefore, on the premise that the total amount of Nb and V is not higher than 0.30wt.%, the present invention controls the C content to be 1.20-1.60wt.%.

Silicon: One of the deoxidizing elements in steel, which has a solid solution strengthening effect. The present invention mainly uses its deoxidation function to control the Si content to 0.25-0.75wt.%.

Manganese: A key alloying element to ensure the stability of austenite and work hardening characteristics, the mass ratio of Mn/C should be controlled not less than 10. The present invention controls the Mn content to be 16.0-20.0wt.%.

Chromium: Cr is one of the corrosion-resistant alloy elements, and it can also significantly increase the hardness of high manganese steel. However, adding carbides that are easy to form coarse Cr during casting and cooling in conventional high manganese steel makes the slab very brittle, which often leads to Cracking; and this kind of coarse carbide is difficult to eliminate through water toughening treatment, thus significantly reducing the impact toughness. The invention controls the Cr content to be 3.00-5.00wt.%, which breaks through the limitation of the Cr content of the traditional high manganese steel. The present invention alleviates or even eliminates its adverse impact on impact toughness through Al alloying.

Aluminum: Al is one of the corrosion-resistant alloying elements, and can also inhibit the formation of carbides. The present invention finds that the Cr content in high manganese steel is not less than 3.00wt%, and when the Al/Cr mass ratio is not less than 1:5, the Al effect on The formation of Cr carbides in high manganese austenite has a strong inhibitory effect. If the Al content is too low, the effect of inhibiting the formation of carbides is not significant; if the Al content is too high, the density will be reduced more, which is not conducive to the technical economy of wear-resistant steel. Therefore, the present invention controls the Al content to be 1.00-2.00wt.%.

Niobium: Nb begins to precipitate during the solidification process of high manganese steel, and it precipitates together with V during the solid solution treatment in the late solidification and water toughening treatment. These MC phases not only have high hardness, can increase hardness and wear resistance, but also can inhibit The austenite grain grows to improve the impact toughness. According to the solid solubility product formula of MC and the control idea of grain refinement, the content of Nb and C changes synergistically, and the mass ratio of Nb/C should be controlled at 1:30-1:15. Therefore, the present invention controls the Nb content to be 0.04%-0.10%wt.

Vanadium: A part of V and Nb are co-precipitated to increase hardness and wear resistance, and refine high manganese austenite grains; another part of V is solid solution, which also increases the hardness of high manganese steel. According to the solid solubility product formula of MC and the control idea of partial solid solution, the content of V, Nb, and C changes synergistically, the mass ratio of V/C is controlled at 1:12～1:8, and the total amount of V and Nb does not exceed 0.30wt.%, the V/Nb mass ratio is controlled to be greater than 2. Therefore, the present invention controls the V content to be 0.10%-0.20wt.%.

Phosphorus: an impurity element in steel, which significantly reduces the plasticity and toughness. For high manganese steel, the present invention controls its content within 0.030wt.%.

Sulfur: an impurity element in steel, which significantly reduces the plasticity and toughness. For high manganese steel, the present invention controls its content within 0.015wt.%.

The advantage of the present invention is that: the Cr-Al-Nb-V alloyed high-wear-resistant high-manganese cast steel of the present invention breaks through the limitation of the Cr content of traditional high-manganese steels, and adopts the technical idea of Al alloying to suppress coarse Cr carbides, so that The carbide size of Cr is controlled below 5 microns. At the same time, Nb and V compound microalloying are used to refine the austenite grains, so that the austenite grains are controlled at 50-100 microns, which does not reduce the impact toughness, but improves the impact wear resistance. The impact and wear resistance of the slab after water toughening treatment is 30-50% higher than that of ZG120Mn17Cr2. Due to the high content of corrosion-resistant alloy elements such as Cr and Al, its advantages in impact, wear and abrasion resistance are more obvious in a slightly corrosive environment.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a small part of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The chemical compositions of the steels of Examples 1#-3# of the present invention are shown in Table 1. After being smelted in a vacuum induction furnace, protective mold casting is carried out, and after the water toughening treatment at 1080 ° C for 3.5 hours, the impact wear test is carried out on the MLD-10 dynamic abrasive wear tester. The experiment uses a 10kg punch; the impact frequency is 200 times/min; the impact time is 0.5h, 1h, 1.5h; the lower sample is 40Cr; the rotation speed is 200r/min; The example steel and ZG120Mn17Cr2 steel were made into 10×10×30mm ³ samples as feeding materials for experiments. Before and after the experiment, the samples were washed with acetone solution and weighed on an electronic balance with an accuracy of 0.0001g, and the weight loss was measured. It is measured that the 1.5J impact wear resistance of the example steel provided by the present invention is 35%, 38% and 52% higher than that of ZG120Mn17Cr2 respectively.

Table 1 chemical composition

serial number C Si mn Cr Al Nb V p S 1# 1.26 0.35 16.5 3.75 1.21 0.05 0.13 0.022 0.008 2# 1.35 0.25 17.8 3.85 1.34 0.04 0.18 0.028 0.005 3# 1.55 0.42 18.9 4.65 1.8 0.1 0.15 0.013 0.012

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of changes or modifications within the technical scope disclosed in the present invention. Replacement should be covered within the protection scope of the present invention.

Claims (8)

1. A kind of 1. high abrasion high manganese cast steel of Cr-Al-Nb-V alloyings, it is characterised in that：Chemical composition C：1.20~ 1.60wt.%, Si：0.25~0.75wt.%, Mn：16.0~20.0wt.%, Cr：3.00~5.00wt.%, Al：1.00~ 1.30wt.%, Nb：0.04~0.10wt.%, V：0.10~0.20wt.%, P<0.03wt.%, S<0.015wt.%, surplus It is percetage by weight for Fe and inevitable impurity；Al/Cr mass ratioes are not less than 1:5.
2. 2. the high abrasion high manganese cast steel of Cr-Al-Nb-V alloyings as claimed in claim 1, it is characterised in that：Chemical composition C： 1.20~1.35wt.%, Si：0.25~0.35wt.%, Mn：16.0~18.0wt.%, Cr：3.00~3.50wt.%, Al： 1.00~1.30wt.%, Nb：0.04~0.07wt.%, V：0.10~0.13wt.%, P<0.01wt.%, S< 0.010wt.%, surplus are Fe and inevitable impurity, are percetage by weight.
3. 3. the high abrasion high manganese cast steel of Cr-Al-Nb-V alloyings as claimed in claim 1, it is characterised in that：Chemical composition C： 1.50~1.60wt.%, Si：0.50~0.75wt.%, Mn：18.5~20.0wt.%, Cr：4.00~5.00wt.%, Al： 1.00~1.30wt.%, Nb：0.08~0.10wt.%, V：0.15~0.20wt.%, P<0.03wt.%, S< 0.015wt.%, surplus are Fe and inevitable impurity, are percetage by weight.
4. 4. the high abrasion high manganese cast steel of Cr-Al-Nb-V alloyings as claimed in claim 1, it is characterised in that：Nb, V total amount are not Higher than 0.30wt.%.
5. 5. the high abrasion high manganese cast steel of Cr-Al-Nb-V alloyings as claimed in claim 1, it is characterised in that：Mn/C mass ratioes Control is not less than 10.
6. 6. the high abrasion high manganese cast steel of Cr-Al-Nb-V alloyings as claimed in claim 1, it is characterised in that：Nb/C mass ratioes It should control as 1:30~1:The control of 15, V/C mass ratioes is 1:12~1:The control of 8, V/Nb mass ratioes is more than 2.
7. 7. the high abrasion high manganese cast steel of Cr-Al-Nb-V alloyings as claimed in claim 1, it is characterised in that：Cr carbon in steel Compound size is below 5 microns, and austenite crystal is at 50~100 microns.
8. 8. the preparation method of the high abrasion high manganese cast steel of the Cr-Al-Nb-V alloyings as described in one of claim 1-7, it is special Sign is：Raw material are mixed by potassium steel composition and weight/mass percentage composition and are put into vacuum induction heating furnace, fully after fusing Be incubated 8~10 minutes again and potassium steel water be made, after coming out of the stove casting form casting, using the heat treatment mode of heat stepwise, first Casting is warming up to 750 DEG C -850 DEG C with 100-150 DEG C/h speed and is incubated 1~2 hour, is then continued with stove heat by casting It is warming up to 1000 DEG C~1200 DEG C and is incubated 1~4 hour, finally comes out of the stove and be cooled to room temperature.