Influence of Route Multiplicity and Drawing Rate on Microhardness Distribution Over Steel Wire Cross Section

Metallurgist - An experimental and finite element study of the effect of the multiplicity of wire drawing regime stages and wire drawing speed on microhardness distribution in steel wire cross...     

Microstructures and Mechanical Properties of as-Drawn and Laboratory Annealed Pearlitic Steel Wires

Near eutectoid fully pearlitic wire rod (5.5 mm diameter) was taken through six stages of wire drawing (drawing strains of 0 to 2.47). The as-drawn (AD) wires were further laboratory annealed (LA) to re-austenitize and reform the pearlite. AD and LA grades, for respective wire diameters, had similar pearlite microstructure: interlamellar spacing (λ) and pearlite alignment with the wire axis. However, LA grade had lower hardness (for both phases) and slightly lower fiber texture and residual stresses in ferrite. Surprisingly, essentially identical tensile yield strengths in AD and LA wires, measured at equivalent spacing, were found. The work hardened AD had, as expected, higher torsional yield strengths and lower tensile and torsional ductilities than LA. In both wires, stronger pearlite alignment gave significantly increased torsional ductility.     

77MnA线材脆性断裂与心部马氏体分析

在77MnA线材拉拔终端、拉拔中段和拉拔之前发生脆性断裂的试样中都存在心部马氏体,并且,在拉拔中段的试样中马氏体断成竹节状,在拉拔终端的试样中马氏体与屈氏体基体之间存在孔洞。可以认为脆性的马氏体不能在拉拔过程中与屈氏体协调形变是导致试样开裂的原因。心部马氏体中铬、锰等稳定奥氏体的元素明显偏高,因此,77MnA线材脆性断裂与成分偏析也有一定关系。     

Structure and Properties of Carbon Steel Wire in Drawing

A method of continuous deformational nanostructuring of wire is described. In the method, a continuously moving wire is subjected simultaneously to tensile deformation in drawing, flexural deformation on passing through a roller system, and torsional deformation. This combination permits wide variation in its mechanical properties, ensuring both high strength and plasticity. The benefits of such deformation are the use of a tool already employed in the production of metal components; compatibility with the speeds of coarse and moderate wire drawing; and simplicity of the equipment. Laboratory apparatus for this method is described. Carbon steel 50 wire is selected for investigation, since it in great demand. The chemical composition and mechanical properties of the wire in the initial state are described. Experiments are conducted to investigate the effectiveness of the proposed differential nanostructuring in producing ultrafine-grain structure in the wire. The deformation conditions of the wire are described, as well as the drawing process. The transverse and longitudinal microstructure of the carbon steel 50 wire at the surface and in the center after different types of deformational treatment is investigated. In the experiments, the influence of the type of deformational treatment on the microstructure of the steel and its anisotropy over the wire cross section is established. The compliance of the wire’s mechanical properties with current standards is verified. After all types of treatment, its mechanical properties are consistent with State Standard GOST 17305–91. Metallographic data and mechanical test results after combined deformational treatment indicate that such combinations of deformation provide a promising approach to creating ultrafine-grain structure in carbon wire.     

High-speed drawing of steel wire

The increase in productivity due to increase in the drawing speed may be largely lost as a result of more frequent shutdown of the equipment associated with the replacement of worn dies and with wire fracture. The influence of the tool parameters on its wear and the wire fracture is analyzed. Recommendations are made regarding parameter optimization and organization of die purchase, manufacture (repair), and operation.     

影响拉丝模使用寿命因素分析及改进的措施

通过多年来的实践总结,从拉丝模模芯选用与热装配钢套的精度,拉丝模工作区的几何尺寸设计,拉丝模工作区的加工,拉拔钢丝的质量和润滑方面分析了影响拉丝模使用寿命的因素。通过分析知道要保证拉丝模有很好的使用寿命,就必须要从拉丝模选材、设计、加工等方面综合考虑,从而提高产品质量,降低成本消耗。     

浅谈铜拉丝润滑油的管理与控制

在铜线拉制的过程中,拉丝润滑油是一个很重要的辅助材料,正确的使用和管理铜线拉丝润滑油,对进一步提高拉丝质量,降低生产成本有重要意义,主要介绍了铜拉丝润滑油的贮存与保管、乳化液的配制、作用、以及乳化液的维护和管理,还对铜拉丝润滑油废液的处理进行了介绍。     

铜杆线拉伸质量问题分析及预防对策

铜杆线拉伸过程中出现毛刺、刮伤甚至断裂,这大大影响铜杆线拉伸的生产效率和拉伸质量。特别是随着多头拉丝机的使用以及电子探伤的广泛应用,对铜杆线提出了更高的质量要求。准确鉴别拉伸铜杆线的质量缺陷,是准确判定原因并采取有效预防措施的前提。     

铜线高速拉拔过程数值模拟及质量控制

为了掌握铜线拉拔过程铜线的变形规律及其不同模具对拉拔过程的影响,通过对拉丝模具几何尺寸和铜线塑性变形的受力分析,建立拉拔变形模型并利用DEFORM-3D有限元对拉拔过程进行模拟,求解不同模角参数下铜线应力应变场和损伤场的变化规律,获得最佳的拉拔模角参数,减少模具磨损延长了模具寿命;同时分析了不同拉丝速度下铜线的变形规律,优化了拉丝工艺参数。     

The micro structure of high carbon low alloy steel for easy drawing

For better processing performance of high carbon low alloy steel wire rod,an investigation about the influence of cementite lamellar spacing on wire ’easy drawing’ performance is completed.It is pointed out that too thin cementite lamellar spacing(<80 um) reduces the strain hardening level of wire drawing, and reduce the torsion performance of drawn wire at same time.For the wire or wire rod from industrial production,compared with the micro-structure with troostite,the micro-structure with sorbite or sorbite mixed with pearlite is more suitable to the drawing process with high reduction ratio.     

硬线钢拉拔断裂机理及连铸工艺优化

 硬线钢除了要求良好的力学性能,还要求良好的加工性能,但硬线钢盘条在拉拔过程中常发生断丝,给加工的连续性带来巨大危害。为了减少硬线钢的拉拔断丝,对其拉拔断裂机理进行了研究,并开展了相应的连铸工艺优化。首先对82B硬线钢拉拔断丝试样进行了分析,通过对断裂试样的断口和纵剖面分析,结合对应的连铸坯内部质量检测,得出连铸坯中心缺陷及偏析对硬线钢拉拔断裂的影响机制为促进了盘条中心渗碳体膜的生成,导致了裂纹的产生和扩展。然后通过施加电流为350 A、频率为6.0 Hz的连铸凝固末端电磁搅拌,降低浇铸时钢水过热度至30 ℃以下等措施,82B硬线钢连铸坯中心缩孔和中心偏析度分别降低至0.5级和1.08以下,82B硬线钢拉拔断丝率由优化前的10~15 次/百t显著下降到4~5 次/百t。     

Q/SMGT001-1998拉丝用低碳钢热轧圆盘条标准述评

叙述了拉丝用低碳钢热轧圆盘条标准的制定过程,分析了同类产品标准参数的对比情况及发展趋势,对拉丝用低碳钢盘条标准实施、修订提出探讨.     

70钢盘条拉拔断裂的原因分析

70钢盘条在拉拔时发生断裂,经对盘条拉拔工艺和盘条材质进行分析,认为盘条心部存在网状渗碳体是造成拉拔断裂主要原因.     

Improving the production of special-purpose wire

The drawing of 12X18H10T stainless-steel wire with a cupronickel coating and cadmium-plated carbon-steel wire is considered. The quality of zinc-plated carbon wire is shown to depend on the drawing temperature, which must be stable.     

电塑性加工对钢丝的摩擦学特性和表面质量的影响

电塑性反拔丝是指在普通拔丝工艺过程中引入高能脉冲电流对工件进行电刺激的新型加工方法,经电塑性拔制的钢丝表面质量有明显的提高。由于高能脉冲电流的引入,使钢丝在拔制过程中的动摩擦系数有明显降低,拔制力大幅度下降,材料的塑性得到提高。     

Controlled drawing to produce desirable hardness and microstructural gradients in alloy 302 wire

The production of a macroscopically duplex microstructure in stainless steel alloy 302 wire, fine grains on the wire surface and coarse grains at the wire interior, was investigated by systematically varying the drawing angle from 8 to 32 deg and the reduction from 1 to 15 pct. The measured hardness gradient was correlated to the microstructure after heat treating at 1000 °C for 0.5 hours. It was determined that the wire surface must exceed a hardness level of 207 KHN for recrystallization to a fine grain size, while the wire core must be hardened to a level between 166 and 207 KHN for grain growth. The deformation zone geometry parameter (Δ) for wire drawing, which is conventionally employed to give a relative measure of the strain distribution in a wire workpiece as a function of die angle and reduction, was utilized in the design of the experimental drawing schedules. The magnitude of measured hardness gradients and the corresponding calculated value of Δ were found to vary similarly with die angle but differently with reduction. At constant total reduction, multiple- and single-step drawing schedules produced equivalent hardness gradients, even though the calculated values for Δ indicated that the former would give a steeper gradient. Wires with two widely differing grain size gradients, coarse and fine vs. fine and coarse at the wire surface and center, were headed. The wire with fine grains on the surface had the higher resistance to surface cracking.     

大拉铜线拉制过程中断线的原因分析及对策

大拉铜线生产大多采用高速连续生产,控制生产过程中断线成了确保生产稳定的首要条件.通过对大拉铜线断线的分析,探索了断线的产生原因,在缺陷分析及生产实践的基础上提出了解决对策,认为通过优化原材料、设备优化、工艺控制等措施可以大大降低断线的产生.     

塔轮式多模拉丝工艺配模设计数学模型及其应用

配模计算公式能方便快捷地计算各模序配模工艺参数;滑移率计算公式有助于工艺设计时拉丝机塔轮选型;有助于处理拉丝过程中出现的断丝问题。     

Effect of cementite morphology on pearlitic wire drawing deformation

A comparative study was conducted on the effects of lamellar cementites and globular cementites on the cold drawing process and the mechanical properties of pearlitic wire steel, with the help of metallographic microscope, scanning electron microscope, transmission electron microscope, tensile tester and hardness tester. The lamellar cementites showed the deformation capacity to some extent during the cold drawing process. As the drawing strain increased, the pearlitic wire with globular cementites evolved into the fibrous form gradually and no obvious defects were found in the microstructure. The globular cementites turned to the drawing direction without any deformation of itself during the deformation process. And micro- cracks occurred in the cementite/ferrite interface due to stress concentration caused by pinning dislocations in spherical cementites. The strength and hardness of both pearlitic wires gradually increased as the drawing strain rose. And the pearlitic wire with lamellar cementites had a higher drawing hardening rate. The ferrite <110> texture formed in both pearlitic wires during the cold drawing process. Compared with the globular pearlite, the pearlitic wire with lamellar cementites had higher ferrite <110> texture intensity. And the difference of their ferrite <110> texture intensity became bigger and bigger as the drawing strain increased.     

大应变变形珠光体钢丝微观组织结构的研究

  采用扫描电镜（SEM）观察了以不同应变量拉拔变形后SWRH72A钢丝的显微组织变化,并测量了钢丝力学性能、磁学性能随应变量增大的变化趋势。试验结果表明,随着拉拔变形应变量的增大,珠光体片层间距逐渐减小,钢丝强度随之升高。由于变形应变量的增大,微缺陷密度升高,钢丝矫顽力Hc和剩余磁化强度Mr都随之变大。而应变量较小时,钢丝比饱和磁化强度基本不变,为227.87 emu/g。当应变量增大到2.60时,样品的比饱和磁化强度升高到233.55 emu/g,计算得知钢丝中渗碳体的质量分数由未变形状态的10.8%降至8.6%。