WO2022160536A1

WO2022160536A1 - Steel for inner raceway of constant velocity universal joint and production method therefor

Info

Publication number: WO2022160536A1
Application number: PCT/CN2021/097026
Authority: WO
Inventors: 陈敏; 罗元东; 白云; 李锋; 尹青; 吴小林; 李文彬
Original assignee: 江阴兴澄特种钢铁有限公司
Priority date: 2021-01-27
Filing date: 2021-05-29
Publication date: 2022-08-04
Also published as: CN112981236A; CN112981236B

Abstract

The present invention relates to steel for inner raceway of a constant velocity universal joint and a production method therefor. The steel comprises the following chemical components in percentage by weight (wt%): 0.15-0.25% of C, 0.01-0.15% of Si, 0.25-0.75% of Mn, 0.80-1.30% of Cr, 0.001-0.003% of B, 0.010-0.040% of Ti, less than or equal to 0.015% of S, less than or equal to 0.025% of P, less than or equal to 0.25% of Ni, less than or equal to 0.20% of Mo, less than or equal to 0.30% of Cu, less than or equal to 0.05% of Al, less than or equal to 0.0010% of Ca, less than or equal to 0.0010% of O, less than or equal to 0.04% of As, less than or equal to 0.03% of Sn, less than or equal to 0.005% of Sb, and less than or equal to 0.002% of Pb, with the balance being Fe and inevitable impurities. The production process comprises primary smelting, refining, vacuum degassing, continuous casting, continuous rolling, annealing, and finishing. The hardness of the steel is less than or equal to 80 HRB; a microscopic structure is ferrite and pearlite; the austenite grain size of the steel is greater than or equal to 6 grade; the banded structure of the steel is graded according to GB/T 13299 and does not exceed 2.0 grade. The hardenability of the tail end of the steel is evaluated according to a GB/T 225 method, and the hardenability of the J5 point is 36-44 HRC, and the hardenability of the J13 point is 24-32 HRC. The steel for the inner raceway of the constant velocity universal joint belongs to novel carburized steel for a universal joint inner raceway, and meets the hardenability, wear resistance, and cold forging performance of the steel for the universal joint inner raceway.

Description

一种等速万向节内滚道用钢及其生产方法Steel for inner raceway of constant velocity universal joint and production method thereof

技术领域technical field

本发明属于特种钢冶炼技术领域，具体涉及一种等速万向节内滚道(星形套)用渗碳钢及生产方法。The invention belongs to the technical field of special steel smelting, and in particular relates to a carburized steel for inner raceways (star sleeves) of constant velocity universal joints and a production method.

背景技术Background technique

万向节是汽车传动***的重要部件，在汽车传动系及其它***中，为了实现一些轴线相交或相对位置经常变化的转轴之间的动力传递，必须采用万向传动装置。目前，轿车上常用的等速万向节是球笼式万向节，球笼式万向节的作用是将发动机的动力从变速器传递到两个前车轮，驱动轿车高速行驶。它主要有外滚道(球形壳)、内滚道(星形套)、保持架(球笼)、钢珠等主要零件组成。由于等速万向节传递繁重的驱动力矩，随受负荷重，传动精度高，需求量很大，又是安全件，因此其主要零件均采用精锻件加工而成。The universal joint is an important part of the automobile transmission system. In the automobile transmission system and other systems, in order to realize the power transmission between the rotating shafts whose axes intersect or whose relative positions frequently change, a universal transmission device must be used. At present, the constant velocity joints commonly used in cars are spherical joints. The function of the spherical joints is to transmit the power of the engine from the transmission to the two front wheels to drive the car at high speed. It is mainly composed of outer raceway (spherical shell), inner raceway (star sleeve), cage (ball cage), steel balls and other main parts. Because the constant velocity universal joint transmits heavy driving torque, bears heavy load, high transmission precision, large demand, and is a safety part, its main parts are all made of precision forgings.

现代汽车工业的竞争日趋激烈，对汽车的动力性、操作性、舒适性及安全性有更高的要求，再加上能源及环境方法的要求，所以在设计汽车重要功能性零部件时，必须综合考虑其安全性、功能性、经济性和排放等重要指标，因而对材料提出更高的要求，要求材料在确保性能的前提下更加轻质化。对于汽车用万向节内滚道而言，部件起传动及支撑的作用，还承受交变载荷应力长期作用，因此材料必须具备足够的耐磨性、抗疲劳性及良好的韧性。The competition in the modern automobile industry is becoming increasingly fierce, and there are higher requirements for the power, operability, comfort and safety of automobiles, coupled with the requirements of energy and environmental methods, so when designing important functional parts of automobiles, it is necessary to Considering its important indicators such as safety, functionality, economy and emissions, higher requirements are placed on materials, requiring materials to be lighter on the premise of ensuring performance. For the inner raceway of the universal joint for automobiles, the components play the role of transmission and support, and also bear the alternating load stress for a long time. Therefore, the material must have sufficient wear resistance, fatigue resistance and good toughness.

当前等速万向节内滚道通常选用材料为20CrNiMo，常用加工方式为棒材下料-热锻造成型-机加工-渗碳淬火热处理-磨加工。热锻时材料塑性好，利于成型，但加工精度低，材料利用率低，能耗高。而冷锻成型后车削量少、材料利用率高，节约能源，降低生产成本，但由于等速万向节内滚道变形率大，若采用冷锻，对材料的冷锻性能提出苛刻的要求，即要求材料具备良好的塑性和韧性，同时根据万向节内滚道的使用要求，还需具备良好的耐磨性和一定的淬透性。At present, the inner raceway of the constant velocity joint is usually made of 20CrNiMo, and the common processing method is bar blanking - hot forging - machining - carburizing and quenching heat treatment - grinding. During hot forging, the material has good plasticity and is conducive to forming, but the machining accuracy is low, the material utilization rate is low, and the energy consumption is high. However, due to the large deformation rate of the inner raceway of the constant velocity universal joint, if cold forging is used, the cold forging performance of the material is put forward. , that is, the material is required to have good plasticity and toughness, and at the same time, according to the use requirements of the inner raceway of the universal joint, it also needs to have good wear resistance and certain hardenability.

此外，钢中的非金属夹杂物会破坏金属的连续性和均匀性。根据使用条件，在交变应力的作用下，夹杂物易于引起应力集中，成为疲劳裂纹源，容易形成裂纹，降低产品的使用寿命。为提高最终产品的使用寿命，必须提高钢材纯净度，尽可能降低钢中非金属夹杂物。In addition, non-metallic inclusions in steel can disrupt the continuity and uniformity of the metal. According to the conditions of use, under the action of alternating stress, the inclusions tend to cause stress concentration, become the source of fatigue cracks, easily form cracks, and reduce the service life of the product. In order to improve the service life of the final product, it is necessary to improve the purity of the steel and reduce the non-metallic inclusions in the steel as much as possible.

目前的20CrNiMo钢，其合金含量高，生产成本高，而且由于合金含量高，热轧棒材的原始组织除铁素体+珠光体外，往往还有贝氏体组织，硬度高，塑性差，不适于冷锻用途。The current 20CrNiMo steel has high alloy content and high production cost, and due to the high alloy content, the original structure of the hot-rolled bar often has a bainite structure in addition to ferrite + pearlite, which has high hardness, poor plasticity and discomfort. For cold forging purposes.

发明内容SUMMARY OF THE INVENTION

为克服现有20CrNiMo钢作为等速万向节内滚道用钢的缺点，本发明提出一种等速万向节内滚道用渗碳钢，协调材料的淬透性和冷锻特性。调节该材料的热轧态原始组织为铁素体+珠光体，同时在成分设计时采用低硅钢的设计，在确保材料淬透性的同时满足材料的冷锻加工性能。In order to overcome the shortcomings of the existing 20CrNiMo steel as the steel for the inner raceway of the constant velocity universal joint, the present invention proposes a carburized steel for the inner raceway of the constant velocity universal joint, which can coordinate the hardenability and cold forging properties of the material. The hot-rolled original structure of the material is adjusted to be ferrite + pearlite, and the design of low-silicon steel is adopted in the composition design, so as to ensure the hardenability of the material and meet the cold forging performance of the material.

本申请钢材的主要技术指标如下：The main technical indicators of the steel in this application are as follows:

硬度≤80HRB，显微组织为铁素体+珠光体，钢材的奥氏体晶粒度≥6级；钢材末端淬透性按照GB/T 225的方法评定，满足J5点：36-44HRC，J13点：24-32HRC；钢材带状组织按GB/T 13299评级，不超过2.0级；非金属夹杂物按GB/T 10561 A法检验，其中脆性不可变形夹杂物B细≤1.5级、B粗≤1.0级、D细≤1.0级、D粗≤0.5级、Ds≤1.0级。前述性能更适应冷锻加工。The hardness is ≤80HRB, the microstructure is ferrite + pearlite, and the austenite grain size of the steel is ≥6; Point: 24-32HRC; steel band structure is graded according to GB/T 13299, no more than 2.0; non-metallic inclusions are tested according to GB/T 10561 A method, of which brittle non-deformable inclusions B fine ≤ 1.5, B coarse ≤ 1.0 grade, D fine ≤1.0 grade, D coarse ≤0.5 grade, Ds≤1.0 grade. The aforementioned properties are more suitable for cold forging.

本发明解决上述问题所采用的技术方案为：一种等速万向节内滚道用钢，化学成分wt％为C：0.15～0.25％，Si：0.01～0.15％，Mn：0.25～0.75％，Cr：0.80～1.30％，B：0.001～0.003％，Ti：0.010～0.040％，S≤0.015％，P≤0.025％，Ni≤0.25％，Mo≤0.20％，Cu≤0.30％，Al≤0.05％，Ca≤0.0010％，O≤0.0010％，As≤0.04％，Sn≤0.03％，Sb≤0.005％，Pb≤0.002％，余量为Fe及不可避免的杂质。The technical scheme adopted by the present invention to solve the above problems is: a steel for inner raceway of constant velocity universal joint, the chemical composition wt% is C: 0.15-0.25%, Si: 0.01-0.15%, Mn: 0.25-0.75% , Cr: 0.80～1.30%, B: 0.001～0.003%, Ti: 0.010～0.040%, S≤0.015%, P≤0.025%, Ni≤0.25%, Mo≤0.20%, Cu≤0.30%, Al≤0.05 %, Ca≤0.0010%, O≤0.0010%, As≤0.04%, Sn≤0.03%, Sb≤0.005%, Pb≤0.002%, the balance is Fe and inevitable impurities.

上述化学成分的设置依据/原理如下：The basis/principle of setting the above chemical composition is as follows:

1)C含量的确定1) Determination of C content

C是确保钢材耐磨性所必须的元素，提高钢中的碳含量将会增加它的马氏体转变能力，从而提高它的硬度和强度，进而提高耐磨性。但过高的C含量对钢的韧性不利。另外，过高的C含量也会导致严重的中心C偏析从而影响钢材的芯部韧性。本发明控制其含量为0.15～0.25％。C is an element necessary to ensure the wear resistance of steel. Increasing the carbon content in the steel will increase its martensitic transformation ability, thereby increasing its hardness and strength, thereby improving wear resistance. But too high C content is detrimental to the toughness of steel. In addition, too high C content will also lead to severe central C segregation and thus affect the core toughness of the steel. The present invention controls its content to be 0.15-0.25%.

2)Si含量的确定2) Determination of Si content

Si为本发明中的关键元素。Si固溶在铁素体相中，有较强的固溶强化作用，能显著提高铁素体强度，但同时降低铁素体的塑性和韧性。Si在炼钢时作为脱氧元素添加到钢材中。本发明用于冷锻万向节内滚道用钢，要求材料有良好的冷锻性能，也就是要求钢中铁素体优良的塑性和韧性。因此，本发明的钢材Si含量要尽量低，目的是尽量降低铁素体中固溶的Si含量，发挥铁素体的塑性极限，所以Si含量的设定范围0.01～0.15％。Si is a key element in the present invention. Si is solid-dissolved in the ferrite phase and has a strong solid solution strengthening effect, which can significantly improve the strength of the ferrite, but at the same time reduce the plasticity and toughness of the ferrite. Si is added to steel as a deoxidizing element during steelmaking. The invention is used for cold forging steel for the inner raceway of universal joints, and the material is required to have good cold forging properties, that is, the ferrite in the steel is required to have excellent plasticity and toughness. Therefore, the content of Si in the steel of the present invention should be as low as possible, in order to reduce the content of Si in solid solution in the ferrite as much as possible and exert the plastic limit of the ferrite, so the setting range of the Si content is 0.01-0.15%.

3)Mn含量的确定3) Determination of Mn content

Mn作为炼钢过程的脱氧元素，是对钢的强化有效的元素，起固溶强化作用。而且Mn能提高钢的淬透性，改善钢的热加工性能。Mn能消除S(硫)的影响：Mn在钢铁冶炼中可与S形成高熔点的MnS，进而消弱和消除S的不良影响。但Mn含量高，会降低钢的韧性。本发明的Mn含量控制在0.25～0.75％。As a deoxidizing element in the steelmaking process, Mn is an element effective in strengthening steel and plays a role in solid solution strengthening. Moreover, Mn can improve the hardenability of steel and improve the hot workability of steel. Mn can eliminate the influence of S (sulfur): Mn can form high melting point MnS with S in iron and steel smelting, thereby weakening and eliminating the adverse effects of S. However, high Mn content will reduce the toughness of steel. The Mn content of the present invention is controlled at 0.25-0.75%.

4)Cr含量的确定4) Determination of Cr content

Cr是碳化物形成元素，能够提高钢的淬透性、耐磨性和耐腐蚀性能。但Cr含量过高，钢材的硬度过大，不利于客户加工使用，综上分析，本发明Cr含量的范围确定为0.80-1.30％。Cr is a carbide-forming element that can improve the hardenability, wear resistance and corrosion resistance of steel. However, if the Cr content is too high, the hardness of the steel is too large, which is unfavorable for customers to process and use. Based on the above analysis, the range of the Cr content in the present invention is determined to be 0.80-1.30%.

5)Al含量的确定5) Determination of Al content

Al作为钢中脱氧元素加入，除为了降低钢水中的溶解氧之外，Al与N形成弥散细小的氮化铝夹杂可以细化晶粒。但Al含量过多时，钢水熔炼过程中易形成大颗粒Al ₂O ₃等脆性夹杂，降低钢水纯净度，影响成品的使用寿命。本发明Al含量的范围确定为≤0.05％。 Al is added as a deoxidizing element in steel. In addition to reducing dissolved oxygen in molten steel, Al and N form finely dispersed aluminum nitride inclusions to refine grains. However, when the Al content is too large, brittle inclusions such as large particles of Al ₂ O ₃ are easily formed during the molten steel smelting process, which reduces the purity of the molten steel and affects the service life of the finished product. The range of the Al content in the present invention is determined to be ≤ 0.05%.

6)B含量的确定6) Determination of B content

B能提高钢的淬透性，还能提高钢的高温强度，并且在钢中能起到强化晶界的作用，本发明B含量的范围确定为0.001-0.003％。B can improve the hardenability of steel and the high-temperature strength of steel, and can strengthen grain boundaries in steel.

7)Ti含量的确定7) Determination of Ti content

钛是钢中强脱氧剂。它能使钢的内部组织致密，细化晶粒。但Ti在钢中会形成碳氮化钛夹杂物，这种夹杂物坚硬、呈棱角状，严重影响材料的疲劳寿命，本发明Ti含量的范围确定为0.01-0.04％。Titanium is a strong deoxidizer in steel. It can make the internal structure of the steel dense and refine the grains. However, Ti will form titanium carbonitride inclusions in steel, which are hard and angular, and seriously affect the fatigue life of the material. The range of Ti content in the present invention is determined to be 0.01-0.04%.

8)Ca含量的确定8) Determination of Ca content

Ca含量会增加钢中点状氧化物的数量和尺寸，同时由于点状氧化物硬度高，塑性差，在钢变形时其不变形，容易在交界面处形成空隙，使钢的性能变差。本发明Ca含量的范围确定为≤0.001％。The Ca content will increase the number and size of point oxides in the steel. At the same time, due to the high hardness and poor plasticity of point oxides, they will not deform when the steel is deformed, and it is easy to form voids at the interface, which will deteriorate the performance of the steel. The range of the Ca content in the present invention is determined to be ≤ 0.001%.

9)O含量的确定9) Determination of O content

氧含量代表了氧化物夹杂总量的多少，氧化物脆性夹杂限制影响成品的使用寿命，大量试验表明，氧含量的降低对提高钢材纯净度特别是降低钢种氧化物脆性夹杂物含量显著有利。本发明氧含量的范围确定为≤0.0010％。The oxygen content represents the total amount of oxide inclusions. The limitation of oxide brittle inclusions affects the service life of the finished product. A large number of experiments show that the reduction of oxygen content is significantly beneficial to improving the purity of steel, especially reducing the content of oxide brittle inclusions in steel. The range of the oxygen content of the present invention is determined to be ≤ 0.0010%.

10)P、S含量的确定10) Determination of P, S content

P在钢中严重引起凝固时的偏析，P溶于铁素体使晶粒扭曲、粗大，且增加冷脆性。本发明P含量的范围确定为≤0.025％。S使钢产生热脆性，降低钢的延展性和韧性，但S能提高钢材的切削性能，本发明S含量的范围确定为≤0.015％。P seriously causes segregation during solidification in steel, and P dissolves in ferrite to distort and coarsen the grains and increase cold brittleness. The range of the P content in the present invention is determined to be ≤ 0.025%. S causes hot brittleness of steel and reduces the ductility and toughness of steel, but S can improve the cutting performance of steel, and the range of S content in the present invention is determined to be ≤0.015%.

11)As、Sn、Sb、Pb含量的确定11) Determination of As, Sn, Sb, Pb content

As、Sn、Sb、Pb等微量元素，均属低熔点有色金属，在钢材中存在，引起零件表面出现软点，硬度不均，因此将它们视为钢中的有害元素，本发明这些元素含量的范围确定为As≤0.04％，Sn≤0.03％，Sb≤0.005％，Pb≤0.002％。As, Sn, Sb, Pb and other trace elements are all non-ferrous metals with low melting point. They exist in steel, causing soft spots on the surface of parts and uneven hardness. Therefore, they are regarded as harmful elements in steel. The content of these elements in the present invention The range of As ≤ 0.04%, Sn ≤ 0.03%, Sb ≤ 0.005%, Pb ≤ 0.002%.

本发明的另一目的是要提供一种等速万向节内滚道用钢的生产方法，生产流程：初炼(电炉或转炉)—炉外精炼—VD或RH真空脱气—连铸—连轧—软化退火—精整—打件入库。Another object of the present invention is to provide a method for producing steel for inner raceway of a constant velocity universal joint. Continuous rolling-softening annealing-finishing-beating into storage.

主要生产工艺特点如下：The main production process features are as follows:

采用优质铁水、废钢及原辅料，降低钢水中有害元素含量。在钢水冶炼过程中采用二次造渣并加强脱氧操作，为了适应低硅钢的生产要求，精炼时脱氧应避免加入含硅的脱氧剂和合金，脱氧采用Al脱氧，初炼出钢时应防止下渣，初炼出钢后到精炼的第一个样的Al含量控制在0.040-0.060％，整个精炼过程Al含量维持在0.025％-0.045％之间，最终保证真空脱气结束后成品Al含量控制在0.015％-0.030％之间，通过钢水冶炼过程中对钢水Al含量的控制间接的将氧含量控制到设计水平。真空脱气后应经进行软吹氩处理，调节氩气流量使钢水液面产生轻微波动即可，软吹氩时间不低于25min，保证非金属夹杂物充分上浮。Use high-quality molten iron, scrap steel and raw and auxiliary materials to reduce the content of harmful elements in molten steel. In the molten steel smelting process, secondary slag making and deoxidation are used. In order to meet the production requirements of low silicon steel, the addition of silicon-containing deoxidizers and alloys should be avoided during deoxidation. Al deoxidation should be used for deoxidation. For slag, the Al content of the first sample after initial smelting and refining is controlled at 0.040-0.060%, and the Al content in the whole refining process is maintained between 0.025%-0.045%, and the final Al content control of the finished product after vacuum degassing is ensured. Between 0.015% and 0.030%, the oxygen content is indirectly controlled to the design level by controlling the Al content of the molten steel in the molten steel smelting process. After vacuum degassing, it should be treated with soft argon blowing. Adjust the argon gas flow to make the molten steel level fluctuate slightly. The soft argon blowing time should not be less than 25min to ensure that non-metallic inclusions are fully floated.

连铸全过程采用防氧化保护浇注，隔绝钢水和空气防止二次氧化，并通过保护渣(低碳钢用的保护渣)吸附夹杂物，连铸过热度为15-35℃，连铸过程采用末端电磁搅拌、轻压下操作以控制钢材的偏析。The whole process of continuous casting adopts anti-oxidation protection pouring, isolates molten steel and air to prevent secondary oxidation, and absorbs inclusions through mold slag (the mold slag for low-carbon steel). Electromagnetic stirring at the end, light pressure operation to control the segregation of steel.

连铸坯入坑缓冷，防止连铸坯开裂，缓冷48小时以上。The continuous casting billet is slowly cooled in the pit to prevent the continuous casting billet from cracking, and the continuous casting billet shall be cooled slowly for more than 48 hours.

连轧前将连铸坯送至中性或弱氧化性气氛的加热炉内加热，设置：预热段温度650-900℃，加热段温度1000-1180℃，均热段温度1100-1200℃，总加热时间在180min 以上，其中均热段保温时间在110min以上。Before continuous rolling, the continuous casting billet is sent to a heating furnace with a neutral or weakly oxidizing atmosphere for heating. The settings are as follows: the temperature of the preheating section is 650-900 °C, the temperature of the heating section is 1000-1180 °C, and the temperature of the soaking section is 1100-1200 °C. The total heating time is more than 180min, and the holding time of the soaking section is more than 110min.

连轧的开轧温度1000℃-1100℃，终轧温度920℃以上，使整个轧制过程都在奥氏体单相区进行，最终轧制成圆钢，轧制完成后圆钢在冷床上缓慢冷却，冷却速度≤10℃/min，使钢中AlN质点细小、均匀、充分析出，从而细化晶粒并防止钢材出现混晶，同时确保钢材进行铁素体+珠光体转变，避免因冷速过快产生贝氏体或马氏体组织。The starting temperature of continuous rolling is 1000℃-1100℃, and the final rolling temperature is above 920℃, so that the whole rolling process is carried out in the austenite single-phase region, and finally rolled into round steel. After the rolling is completed, the round steel is placed on the cooling bed. Slow cooling, the cooling rate is ≤10℃/min, so that the AlN particles in the steel are fine, uniform, and fully analyzed, so as to refine the grains and prevent the mixed crystals of the steel, and at the same time ensure that the steel undergoes ferrite + pearlite transformation to avoid cold Too fast to produce bainite or martensite structure.

为保证钢材的交货硬度，对连轧后的圆钢进行软化退火，软化退火是将轧后圆钢加热到低于再结晶温度并保温，使组织发生恢复，软化退火过程中微观结构不变，目的是将硬度降低至≤80HRB。软化退火温度为500-650℃，保温时间为10h以上，之后随炉冷却至200℃以下后出炉空冷至室温。In order to ensure the delivery hardness of the steel, the round steel after continuous rolling is softened and annealed. Softening annealing is to heat the rolled round steel to a temperature lower than the recrystallization temperature and keep it warm to restore the structure, and the microstructure remains unchanged during the softening annealing process. , the purpose is to reduce the hardness to ≤ 80HRB. The softening annealing temperature is 500-650 °C, the holding time is more than 10h, and then it is cooled to below 200 °C with the furnace, and then air-cooled to room temperature.

与现有技术相比，本发明的优点在于：Compared with the prior art, the advantages of the present invention are:

1)本发明在成分设计时采用低硅钢的设计，并保证钢材的显微组织及硬度要求，在确保材料淬透性的同时满足材料的冷锻性能。1) The present invention adopts the design of low-silicon steel in the composition design, and ensures the microstructure and hardness requirements of the steel, and meets the cold forging performance of the material while ensuring the hardenability of the material.

2)本发明另一关键在于对钢材纯净度和偏析的控制，有效满足万向节内滚道用钢抗疲劳的使用要求。2) Another key point of the present invention lies in the control of the purity and segregation of the steel, which effectively meets the fatigue resistance requirements of the steel used for the inner raceway of the universal joint.

本申请发明了一种新的万向节内滚道用渗碳钢材，满足万向节内滚道用钢材的淬透性、耐磨性及冷锻性能。The present application has invented a new carburized steel for the inner raceway of the universal joint, which can satisfy the hardenability, wear resistance and cold forging performance of the steel for the inner raceway of the universal joint.

附图说明Description of drawings

图1为本发明实施例的典型金相组织图100×；FIG. 1 is a typical metallographic structure diagram 100× of an embodiment of the present invention;

图2为本发明实施例的典型金相组织图1000×；FIG. 2 is a typical metallographic structure diagram 1000× of an embodiment of the present invention;

图3为对比例的金相组织图100×；Fig. 3 is the metallographic structure diagram 100× of the comparative example;

图4为对比例的金相组织图1000×。FIG. 4 is a metallographic structure diagram 1000× of the comparative example.

具体实施方式Detailed ways

以下结合附图对本发明作进一步详细描述，所述实施例是示例性的，旨在用于解释本发明，而不能理解为对本发明的限制。The present invention will be described in further detail below with reference to the accompanying drawings. The embodiments are exemplary, and are intended to be used to explain the present invention, but should not be construed as a limitation of the present invention.

本发明各实施例的化学成分(wt％)见表1、表2。并与对比钢20CrNiMo的化学成分做对比。The chemical composition (wt%) of each embodiment of the present invention is shown in Table 1 and Table 2. And compared with the chemical composition of the comparative steel 20CrNiMo.

表1Table 1

实施例Example

CC

SiSi

MnMn

PP

SS

CrCr

CuCu

NiNi

AlAl

BB

本发明this invention	11	0.180.18	0.030.03	0.520.52	0.0180.018	0.0020.002	1.201.20	0.010.01	0.020.02	0.0180.018	0.00130.0013
本发明this invention	22	0.190.19	0.040.04	0.570.57	0.0160.016	0.0020.002	1.161.16	0.010.01	0.020.02	0.0230.023	0.00120.0012
本发明this invention	33	0.190.19	0.020.02	0.490.49	0.0150.015	0.0010.001	1.151.15	0.020.02	0.030.03	0.0200.020	0.00150.0015
对比钢contrast steel		0.190.19	0.250.25	0.850.85	0.0150.015	0.0050.005	0.560.56	0.030.03	0.510.51	0.0250.025	0.00030.0003

表2Table 2

	实施例Example	MoMo	AsAs	SnSn	SbSb	PbPb	CaCa	TiTi	OO
本发明this invention	11	0.010.01	0.0020.002	0.0030.003	0.0020.002	0.0010.001	0.00020.0002	0.0240.024	0.00080.0008
本发明this invention	22	0.020.02	0.0030.003	0.0020.002	0.0020.002	0.0010.001	0.00020.0002	0.0250.025	0.000780.00078
本发明this invention	33	0.010.01	0.0020.002	0.0020.002	0.0010.001	0.0020.002	0.00010.0001	0.0270.027	0.000730.00073
对比钢contrast steel		0.250.25	0.0030.003	0.0060.006	0.0020.002	0.0010.001	0.00050.0005	0.00300.0030	0.00100.0010

按照表1、表2的化学成分冶炼钢水，并由此生产的钢材纯净度更高，钢材非金属夹杂物按GB/T 10561 A法检验，各实施例钢材的夹杂物水平见表3。The molten steel is smelted according to the chemical composition in Table 1 and Table 2, and the steel produced thereby has higher purity. The non-metallic inclusions in the steel are inspected by the GB/T 10561 A method, and the inclusion levels of the steels in each embodiment are shown in Table 3.

表3table 3

	实施例Example	A细夹杂A fine inclusion	A粗夹杂A coarse inclusion	B细夹杂B fine inclusions	B粗夹杂B coarse inclusions	C细夹杂C fine inclusions	C粗夹杂C coarse inclusions	D细夹杂D fine inclusions	D粗夹杂D coarse inclusions	Ds夹杂Ds inclusions
本发明this invention	11	0～1.00～1.0	0～0.50～0.5	0～0.50～0.5	0～0.50～0.5	00	00	0～0.50～0.5	0～0.50～0.5	0～1.00～1.0
本发明this invention	22	0.5～1.00.5～1.0	0～0.50～0.5	0～0.50～0.5	00	00	00	0～0.50～0.5	0～0.50～0.5	0～0.50～0.5
本发明this invention	33	0～1.00～1.0	0～0.50～0.5	0～0.50～0.5	00	00	00	0～1.00～1.0	0～0.50～0.5	0～0.50～0.5

表4各实施例的末端淬透性性能对比，单位HRC。Table 4 Comparison of end hardenability performance of each embodiment, in HRC.

表4Table 4

	J5J5	J13J13
本发明实施例1Embodiment 1 of the present invention	4040	27.527.5
本发明实施例2Embodiment 2 of the present invention	41.541.5	2727
本发明实施例3Embodiment 3 of the present invention	40.540.5	2828

本发明钢材低倍组织良好，钢材低倍组织按ASTM E381法检验，实施例钢材的低倍组织数据见表5。The low magnification structure of the steel of the present invention is good, and the low magnification structure of the steel is tested by the ASTM E381 method, and the low magnification structure data of the embodiment steel is shown in Table 5.

表5table 5

	CC	RR	SS
本发明实施例1Embodiment 1 of the present invention	1.01.0	1.51.5	1.01.0
本发明实施例2Embodiment 2 of the present invention	1.01.0	1.51.5	1.01.0
本发明实施例3Embodiment 3 of the present invention	1.01.0	1.01.0	1.01.0

表6各实施例钢材的交货硬度，单位HRB。Table 6 Delivery hardness of each embodiment steel, unit HRB.

表6Table 6

	交货硬度Delivery hardness
本发明实施例1Embodiment 1 of the present invention	7575
本发明实施例2Embodiment 2 of the present invention	7878

本发明实施例3Embodiment 3 of the present invention

7777

表7各实施例钢材及对比例的金相组织、带状组织、晶粒度数据见表7。Table 7 The metallographic structure, banded structure and grain size data of each embodiment steel and the comparative example are shown in Table 7.

表7Table 7

本发明实施例及对比例钢材的典型微观结构参见图1-4。The typical microstructures of the steels of the examples of the present invention and the comparative examples are shown in Figs. 1-4.

各实施例的滚等速万向节内滚道用钢的制造流程为电炉或转炉(初炼)—炉外精炼—VD或RH真空脱气—连铸—连轧—软化退火—精整—打件入库。The manufacturing process of the steel for the inner raceway of the constant velocity universal joint of each embodiment is an electric furnace or a converter (primary smelting)—out-of-furnace refining—VD or RH vacuum degassing—continuous casting—continuous rolling—softening annealing—finishing— Pieces into storage.

钢水冶炼时，采用优质铁水、废钢及原辅料，降低钢水中有害元素含量。在钢水冶炼过程中采用二次造渣并加强脱氧操作，为了适应低硅钢的生产要求，精炼时脱氧应避免加入含硅的脱氧剂和合金，脱氧采用Al脱氧，初炼出钢时应防止下渣，初炼出钢后到精炼的第一个样的Al含量控制在0.040-0.060％，整个精炼过程Al含量维持在0.025％-0.045％之间，最终保证真空脱气结束后成品Al含量控制在0.015％-0.030％之间，通过钢水冶炼过程中对钢水Al含量的控制间接的将氧含量控制到设计水平。真空脱气后应经进行软吹氩处理，调节氩气流量使钢水液面产生轻微波动即可，软吹氩时间不低于25min，保证非金属夹杂物充分上浮。When molten steel is smelted, high-quality molten iron, scrap steel and raw and auxiliary materials are used to reduce the content of harmful elements in molten steel. In the molten steel smelting process, secondary slag making and deoxidation are used. In order to meet the production requirements of low silicon steel, the addition of silicon-containing deoxidizers and alloys should be avoided during deoxidation. Al deoxidation should be used for deoxidation. For slag, the Al content of the first sample after initial smelting and refining is controlled at 0.040-0.060%, and the Al content in the whole refining process is maintained between 0.025%-0.045%, and the final Al content control of the finished product after vacuum degassing is ensured. Between 0.015% and 0.030%, the oxygen content is indirectly controlled to the design level by controlling the Al content of the molten steel in the molten steel smelting process. After vacuum degassing, it should be treated with soft argon blowing. Adjust the argon gas flow to make the molten steel level fluctuate slightly. The soft argon blowing time should not be less than 25min to ensure that non-metallic inclusions are fully floated.

连铸全过程采用防氧化保护浇注，隔绝钢水和空气防止二次氧化，并通过低碳钢用保护渣吸附夹杂物，连铸过热度为15-35℃，连铸过程采用末端电磁搅拌、轻压下操作以控制钢材的偏析。连铸方坯的规格为200mm×200mm，连铸坯入坑缓冷，缓冷48小时以上。The whole process of continuous casting adopts anti-oxidation protection pouring, isolates molten steel and air to prevent secondary oxidation, and absorbs inclusions with mold slag for low-carbon steel. The superheat degree of continuous casting is 15-35 °C. A reduction operation to control the segregation of the steel. The specification of the continuous casting billet is 200mm×200mm, and the continuous casting billet is slowly cooled in the pit for more than 48 hours.

连轧是将中间坯送至加热炉内轧制成目标钢材，具体的轧制工艺为：预热段温度控制在650-900℃，加热段温度控制在1000-1180℃，均热段温度控制在1100-1200℃，为保证坯料充分均匀受热，总加热时间在180min以上，均热段温度在110min以上。轧制开轧温度控制在1000℃-1100℃，終轧温度控制在920℃以上，使整个钢材的轧制过程都在奥氏体单相区轧制，最终轧制成Φ30mm-60mm的圆钢，终轧轧制完成后应在冷床上缓慢冷却，冷却速度不超过10℃/min，使钢中AlN质点细小、均匀、充分析出，从而细化晶粒并防止钢材出现混晶，同时确保钢材进行铁素体+珠光体转变。各实施例连轧轧制工艺如下表8所示。Continuous rolling is to send the intermediate billet to the heating furnace to be rolled into the target steel. The specific rolling process is: the temperature of the preheating section is controlled at 650-900 °C, the temperature of the heating section is controlled at 1000-1180 °C, and the temperature of the soaking section is controlled at 650-900 °C. At 1100-1200 ℃, in order to ensure that the billet is fully and evenly heated, the total heating time is more than 180min, and the temperature of the soaking section is more than 110min. The rolling temperature is controlled at 1000℃-1100℃, and the final rolling temperature is controlled above 920℃, so that the whole rolling process of the steel is rolled in the austenite single-phase region, and finally rolled into a round steel of Φ30mm-60mm , After finishing rolling, it should be slowly cooled on the cooling bed, and the cooling rate should not exceed 10 ° C/min, so that the AlN particles in the steel are fine, uniform, and fully analyzed, so as to refine the grains and prevent mixed crystals in the steel, while ensuring the steel. The ferrite + pearlite transformation is carried out. The continuous rolling process of each embodiment is shown in Table 8 below.

表8Table 8

轧制完成后，将轧制的成品棒材进行软化退火处理，以保证钢材硬度满足不超过80HRB的要求，退火温度为500-650℃，保温时间为10h以上，随后随炉冷却至200℃以下后出炉空冷至室温。After the rolling is completed, the rolled finished bar is softened and annealed to ensure that the hardness of the steel does not exceed 80HRB. Then air-cooled to room temperature.

通过上述实施例以及与对比例的对比，采用本申请制造方法可以获得一种满足万向节内滚道用钢材的淬透性、耐磨性及冷锻性能。Through the above examples and the comparison with the comparative example, it is possible to obtain a steel material that satisfies the hardenability, wear resistance and cold forging properties of the steel for the inner raceway of the universal joint by using the manufacturing method of the present application.

除上述实施例外，本发明还包括有其他实施方式，凡采用等同变换或者等效替换方式形成的技术方案，均应落入本发明权利要求的保护范围之内。In addition to the above-mentioned embodiments, the present invention also includes other embodiments, and all technical solutions formed by equivalent transformation or equivalent replacement shall fall within the protection scope of the claims of the present invention.

Claims

一种等速万向节内滚道用钢，其特征在于：所述钢的化学成分wt％为C：0.15～0.25％，Si：0.01～0.15％，Mn：0.25～0.75％，Cr：0.80～1.30％，B：0.001～0.003％，Ti：0.010～0.040％，S≤0.015％，P≤0.025％，Ni≤0.25％，Mo≤0.20％，Cu≤0.30％，Al≤0.05％，Ca≤0.0010％，O≤0.0010％，As≤0.04％，Sn≤0.03％，Sb≤0.005％，Pb≤0.002％，余量为Fe及不可避免的杂质。A steel for constant velocity universal joint inner raceway, characterized in that the chemical composition wt% of the steel is C: 0.15-0.25%, Si: 0.01-0.15%, Mn: 0.25-0.75%, Cr: 0.80 ～1.30%, B: 0.001～0.003%, Ti: 0.010～0.040%, S≤0.015%, P≤0.025%, Ni≤0.25%, Mo≤0.20%, Cu≤0.30%, Al≤0.05%, Ca≤ 0.0010%, O≤0.0010%, As≤0.04%, Sn≤0.03%, Sb≤0.005%, Pb≤0.002%, the balance is Fe and inevitable impurities.
根据权利要求1所述的等速万向节内滚道用钢，其特征在于：所述钢的硬度≤80HRB；显微组织为铁素体+珠光体；钢材的奥氏体晶粒度≥6级；钢材末端淬透性按照GB/T 225的方法评定，满足J5点：36-44HRC，J13点：24-32HRC；钢材带状组织按GB/T 13299评级，不超过2.0级；非金属夹杂物按GB/T 10561 A法检验，其中脆性不可变形夹杂物B细≤1.5级、B粗≤1.0级、D细≤1.0级、D粗≤0.5级、Ds≤1.0级。The steel for constant velocity universal joint inner raceway according to claim 1, characterized in that: the hardness of the steel is less than or equal to 80HRB; the microstructure is ferrite + pearlite; the austenite grain size of the steel is greater than or equal to Grade 6; steel end hardenability is assessed according to the method of GB/T 225, and meets J5 point: 36-44HRC, J13 point: 24-32HRC; steel strip structure is rated according to GB/T 13299, not exceeding 2.0; non-metallic Inclusions are inspected according to GB/T 10561 A method, among which brittle non-deformable inclusions are B fine ≤ 1.5, B coarse ≤ 1.0, D fine ≤ 1.0, D coarse ≤ 0.5, Ds ≤ 1.0.
一种等速万向节内滚道用钢的生产方法，其特征在于：生产流程为初炼—精炼—真空脱气—连铸—连轧—退火—精整，主要生产特点如下，A method for producing steel for inner raceway of a constant velocity universal joint is characterized in that: the production process is primary refining-refining-vacuum degassing-continuous casting-continuous rolling-annealing-finishing, and the main production features are as follows,

在钢水冶炼过程中采用二次造渣并加强脱氧操作，为了适应低硅钢要求，精炼时脱氧应避免加入含硅的脱氧剂和合金，脱氧采用Al脱氧，初炼出钢时应防止下渣，出钢后到精炼的第一个样的Al含量控制在0.040-0.060％，整个精炼过程Al含量维持在0.025％-0.045％之间，最终保证真空脱气结束后成品Al含量控制在0.015％-0.030％之间，通过过程中对钢水Al含量的控制间接的将氧含量控制到设计水平；真空脱气后应经进行软吹氩处理；连铸全过程采用防氧化保护浇注，隔绝钢水和空气防止二次氧化，并通过保护渣吸附夹杂物；In the process of molten steel smelting, secondary slagging and deoxidation are used. In order to meet the requirements of low-silicon steel, the addition of silicon-containing deoxidizers and alloys should be avoided during deoxidation. Al deoxidation should be used for deoxidation. The Al content of the first sample after tapping to refining is controlled at 0.040-0.060%, and the Al content in the entire refining process is maintained between 0.025%-0.045%, and the final Al content of the finished product after vacuum degassing is controlled at 0.015%- Between 0.030%, the oxygen content is indirectly controlled to the design level through the control of the Al content in the molten steel in the process; after vacuum degassing, it should be treated with soft argon blowing; the whole process of continuous casting is poured with anti-oxidation protection to isolate molten steel and air Prevent secondary oxidation and adsorb inclusions through mold slag;

连轧前将连铸坯送至中性或弱氧化性气氛的加热炉内加热，设置：预热段温度650-900℃，加热段温度1000-1180℃，均热段温度1100-1200℃，总加热时间在180min以上，其中均热段保温时间在110min以上；Before continuous rolling, the continuous casting billet is sent to a heating furnace with a neutral or weakly oxidizing atmosphere for heating. The settings are as follows: the temperature of the preheating section is 650-900 °C, the temperature of the heating section is 1000-1180 °C, and the temperature of the soaking section is 1100-1200 °C. The total heating time is more than 180min, and the holding time of the soaking section is more than 110min;

连轧的开轧温度1000℃-1100℃，终轧温度920℃以上，使整个轧制过程都在奥氏体单相区进行，最终轧制成圆钢，轧制完成后圆钢在冷床上缓慢冷却，冷却速度≤10℃/min，缓冷过程微观结构转变为铁素体+珠光体；The starting temperature of continuous rolling is 1000℃-1100℃, and the final rolling temperature is above 920℃, so that the whole rolling process is carried out in the austenite single-phase region, and finally rolled into round steel. After the rolling is completed, the round steel is placed on the cooling bed. Slow cooling, cooling rate ≤ 10℃/min, the microstructure changes to ferrite + pearlite during slow cooling;

软化退火是将轧后圆钢加热到低于再结晶温度并保温，使组织发生恢复，软化退火过程中微观结构不变，目的是降低硬度至≤80HRB。Softening annealing is to heat the rolled round steel below the recrystallization temperature and keep it warm to restore the structure, and the microstructure remains unchanged during the softening annealing process, and the purpose is to reduce the hardness to ≤80HRB.
根据权利要求3所述的等速万向节内滚道用钢，其特征在于：初炼时采用优质铁水、废钢及原辅料，降低钢水中有害元素含量。The steel for the inner raceway of the constant velocity universal joint according to claim 3 is characterized in that: high-quality molten iron, scrap steel and raw and auxiliary materials are used in the initial smelting to reduce the content of harmful elements in the molten steel.
根据权利要求3所述的等速万向节内滚道用钢，其特征在于：真空脱气后进行软吹氩处理，调节氩气流量使钢水液面产生波动，软吹氩时间不低于25min，保证非金属夹杂物充分上浮。The steel for inner raceway of constant velocity universal joint according to claim 3, characterized in that: after vacuum degassing, soft argon blowing treatment is performed, the flow rate of argon gas is adjusted so that the molten steel level fluctuates, and the soft argon blowing time is not less than 25min to ensure that the non-metallic inclusions are fully floated.
根据权利要求3所述的等速万向节内滚道用钢，其特征在于：连铸采用低过热度浇注，连铸过热度为15-35℃，连铸过程中采用末端电磁搅拌、轻压下的操作方式以控制钢材的偏析。The steel for constant velocity universal joint inner raceway according to claim 3, characterized in that: continuous casting adopts low superheat casting, the continuous casting superheat is 15-35 ℃, and the continuous casting process adopts end electromagnetic stirring, light The operation of the reduction to control the segregation of the steel.
根据权利要求3所述的等速万向节内滚道用钢，其特征在于：连铸坯为规格200mm×200mm及以上的连铸方坯，轧制成Φ30mm-60mm的圆钢。The steel for the inner raceway of the constant velocity universal joint according to claim 3, wherein the continuous casting billet is a continuous casting billet with a size of 200mm×200mm and above, and is rolled into a round steel of Φ30mm-60mm.
根据权利要求3所述的等速万向节内滚道用钢，其特征在于：连铸生产线上下来的连铸坯入坑缓冷，缓冷48小时以上。The steel for the inner raceway of the constant velocity universal joint according to claim 3, characterized in that: the continuous casting billets coming off the continuous casting production line are slowly cooled in the pit for more than 48 hours.
根据权利要求3所述的等速万向节内滚道用钢，其特征在于：软化退火温度为500-650℃，保温时间为10h以上，之后随炉冷却至200℃以下后出炉空冷至室温。The steel for constant velocity universal joint inner raceway according to claim 3, characterized in that: the softening annealing temperature is 500-650°C, the holding time is more than 10h, and then it is cooled to below 200°C with the furnace and then air-cooled to room temperature. .