大颗粒碳化物对W4Mo3Cr4VSi钻头性能的影响

生产中发现部分W4Mo3Cr4VSi高速钢钻头出现大颗粒碳化物,导致产品的淬火温度大幅度下降。大颗粒碳化物导致材料中碳化物的弥散度和溶解活性大幅度降低。高速钢的耐火程度亦强烈下降,比正常碳化物材料的耐火温度降低20℃以上。耐火温度的剧烈下降导致钻头的硬度和红硬性的明显降低。大颗粒碳化物以及因其造成的晶粒粗大对钻头的韧性构成危害,是导致钻头断裂和掉块的重要原因。     

W6Mo5Cr4V2高速钢钻头深冷处理工艺试验研究

采用正交试验方法研究W6Mo5Cr4V2高速钢钻头的深冷处理工艺。分析不同深冷处理工艺对材料力学性能的影响,使用电子扫描显微镜观察材料显微组织。试验结果表明,深冷温度是影响深冷效果的最主要因素,深冷保温时间和回火温度次之。深冷处理促使残留奥氏体向马氏体转变,在马氏体基体上析出碳化物颗粒,这是钻头硬度和耐磨性提高的主要原因。     

深冷处理对W4Mo3Cr4VSi钻头性能影响的实验研究

研究深冷处理对高速钢钻头硬度、耐磨性的影响,结果表明,深冷处理可以改变高速钢钻头的显微组织结构.通过显微图(SEM)观察发现,深冷处理促使残余奥氏体向马氏体转变,并在马氏体基体上析出弥散分布的微细碳化物,从而提高了钻头的硬度和耐磨性,钻头使用寿命提高2～4倍.     

通用高速钢W9Mo3Cr4V

制造复杂刀具的材料,高速钢仍占主要地位,尤其在有色金属的切削加工中,还广泛使用高速钢刀具。长期以来,通用高速钢一直沿用W18Cr4V,属高钨系,简称W18。由于其一次碳化物不均匀度大,颗粒度粗,韧性较差,尤其是热塑性低,不能满足热轧各种成型工具的要求。六十年代以来,国际上已普遍使用钨钼系高速钢W6Mo5Cr4V2(简称M2)来代替W18高速钢,但M2钢脱碳严重,在我国现有锻轧     

W9Mo3Cr4V高速钢钻头深冷处理工艺研究

采用正交试验法对W9Mo3Cr4V高速钢深冷处理工艺进行了研究,分析了不同工艺参数对钻头性能的影响,并使用电子扫描显微镜观察了深冷处理前后的显微组织.结果表明,深冷温度对钻头性能影响最大,其次是深冷保温时间,最后是冷却速度.深冷处理促使残余奥氏体向马氏体转变,并在马氏体基体上析出弥散分布的微细碳化物,从而提高了钻头的硬度和耐磨性.     

φ3—10MM麻花钻头调直前的等温淬火工艺

φ3～10mm 高速钢直柄麻花钻头过去采用分级淬火、空冷,然后进行正常回火(回火温度560℃,每次一小时,共三次)。为了消除弯曲变形,要进行人工调直。工人用小锤敲打,边调边检直到合格为止。不仅劳动强度大,调直困难,合格率低,而且钻头容易被敲断。高速钢淬火主要有分级淬火和等温淬火两种。分级淬火后的组织是由淬火马氏体、残余奥氏体和剩余碳化物组成。而淬火马氏体和剩余碳化物都是脆性组织,所以采用分级淬火的钻头,在调直中容易断裂,在使用     

通用高速钢W9Mo3Cr4V

制造复杂刀具的材料,高速钢仍占主要地位,尤其在有色金属的切削加工中,还广泛使用高速钢刀具。长期以来,通用高速钢一直沿用W18Cr4V,属高钨系,简称W18。由于其一次碳化物不均匀度大,颗粒度粗,韧性较差,尤其是热塑性低,不能满足热轧各种成型工具的要求。六十年代以来,国际上已普遍使用钨钼系高速钢W6Mo5Cr4V2(简称M2)来代替W18高速钢,但M2钢脱碳严重,在我国现有锻轧设备及退火设备落后的情况下,许多冶金厂不易解决脱碳严重的问题。此外,M2钢使用了较多的钼和钒,也不符合我国资源情况。     

TC4材料钻削性能试验及优化验证

本文采用M42高速钢钻头进行TC4材料钻削性能试验,分析其切削加工性及刀具窖损机理。并通过试验建立相应的切削力、切削温度、刀具寿命公式。并通过航空发动机TC4材料机匣钻削加工过程进行工艺验证。     

碳化物粘连对M2高速钢大规格丝锥开裂的影响

分析了导致M2(W6M05Cr4V2)高速钢大规格丝锥在机加工过程中产生开裂现象的原因及影响。实验发现在丝锥断口中碳化物堆积粘连,在钢材中碳化物粘连现象严重。碳化物粘连现象是在钢生产过程中热加工温度过高所致,导致钢变得很脆,属于过热质量问题,是造成丝锥开裂的主要原因,并就此提出了对策。     

W6Mo5Cr4V2高速钢插齿刀毛坯的胎模锻造

目前,国内齿轮切削刀具大多采用W6Mo5Cr4V2高速钢材料制成,材料锻造主要以改善刀具毛坯碳化偏析程度为主。高速钢具有很高的耐热性能,在高温下强度高、变形抗力大,增加了锻造成形的难度。本文通过试验研究,提出了在保证W6Mo5Cr4V2高速钢合格碳化物等级的前提下对刀具毛坯进行胎模锻造成形的方法。     

硬质合金群钻钻尖的试验研究

群钻钻尖具有较好的排屑性能,但群钻钻尖参数源于高速工具钢材料,其几何参数不适合于硬质合金。本文设计出一种排屑性能良好的硬质合金群钻钻尖,试验证明其分屑、断屑能力及切削性能优于硬质合金标准钻尖钻头。     

Optimization of cutting parameters on drill bit temperature in drilling by Taguchi method

In this study, the optimization of the cutting parameters on drill bit temperature in drilling was performed. Al 7075 work piece and the uncoated and Firex® coated carbide drills in the experimental were used. The optimization of the cutting parameters was evaluated by Taguchi method. The control factors were considered as the cutting speed, feed rate and cutting tool. Taguchi method was used to determining the settings of cutting parameters. The L₁₈ orthogonal array was used in experimental planning. The most significant control factors affected on drill bit temperature measurements was obtained by using analysis of variance (ANOVA). Taguchi design method exhibit a good performance in the optimization of cutting parameters on drill bit temperature measurements. In addition, the empirical equations of drill bit temperatures were derived by using regression analysis. The obtained equations results compared with the drill bit temperature measurement results. The empirical equations results indicated a good agreement with experimental results.     

Finite element and experimental investigation of temperature changes on a twist drill in sequential dry drilling

The drilling process is highly non-linear. Coupled with a thermo-mechanical machining, localized heating and temperature increases in the workpiece are caused by the rapid plastic deformation of the workpiece and by the friction along the drill-chip interface. The cutting temperature at the tool-chip interface is an important factor which directly affects workpiece surface integrity, tool wear, and hole diameter and cylindricity in the drilling process. In this study, the effects of sequential dry drilling operations on the drill bit temperature were investigated both experimentally and numerically. Drill temperatures were measured by inserting standard thermocouples into the coolant (oil) hole of TiN/TiAlN-coated carbide drills. Experimental studies were conducted using two different workpiece materials, AISI 1040 steel and Al 7075-T651. The drill bit temperature was predicted using a numerical computation with Third Wave AdvantEdge finite element method (FEM) software, which is based on Lagrangian explicit. The results obtained from the experimental study and finite element analyses (FEA) were compared. Reasonable agreement between the measured and calculated drill bit temperature results were found for sequential dry drilling.     

大锥钻表面产生萘状断口的原因分析

生产中发现Φ36mm锥钻出现萘状断口,粗大的晶粒分布在钻头的刃部,在心部没有发现这种现象。萘状断口是高速钢晶粒的二次再结晶,粗大的晶粒对钻头的韧性造成危害。经分析发现在轧制工序设备改造过程中,因更改感应加热的频率、功率和加热时间,造成工件的表层加热温度过高,随后的热处理过程发生二次淬火,使产品出现萘状断口。     

硬地层单牙轮-PDC钻扩联合钻头破岩特性

提出了新型单牙轮-PDC钻扩联合钻头,先依靠单牙轮破岩钻孔,释放地应力,产生岩石损伤,再助推PDC钻头刮切破岩。运用有限元法,建立钻扩联合钻头、双级PDC和常规PDC钻头破岩的非线性动力学模型。通过对岩石本构关系进行D-P准则描述以及确定岩石破碎的判据,分析钻扩联合钻头钻进硬地层的破岩机理,开展了3种钻头动态破岩过程的对比研究。结果表明：钻扩联合钻头在钻进过程中井底井壁的岩石应力得到明显释放,大大提高了岩层可钻性;在硬地层中钻扩联合钻头钻进速度提高的主要原因是拉应力破岩;钻扩联合钻头在硬地层钻进过程中的扭转振动大大降低,破岩效率更高,钻头寿命更长;由于单牙轮领眼破碎岩石的作用,钻扩联合钻头对井底岩石的冲击破碎能力更强,在硬地层中钻进更快。研究结果为新型单牙轮-PDC钻扩联合钻头的研发提供了参考。     

丝锥用HOP2030粉末高速钢的淬火温度研究

本文对丝锥用粉末高速钢HOP2030的淬火温度进行了试验研究。试验表明,HOP2030钢丝锥的淬火温度通常为1140℃-1180℃,淬火晶粒均匀、细小是粉末高速钢的显著特点之一,HOP2030钢丝锥淬火晶粒度应小于10.5号,碳化物粘连和拖尾长度是评定粉末高速钢过热程度的主要标识。     

Effects of different cooling conditions on twist drill temperature

In the past, many researchers have studied wear developed on drilling tools mainly due to the high temperatures generated which accelerate thermally related wear mechanisms and thereby reducing tool life. This paper deals with an experimental investigation on the effect of an internal coolant approach (for different air pressure) on drill bit temperature, comparing it with an external coolant approach and dry cutting. Drill temperatures were measured by inserting standard thermocouples through the coolant (oil) hole of TiN/TiAlN-coated carbide drills. Experimental studies have been conducted using Al 2014 alloy materials. In the drilling tests, cutting conditions had different spindle speeds, coolant approaches and feed rate values. The settings of drilling parameters were determined by using the Taguchi experimental design method. An orthogonal array, the signal-to-noise (S/N) ratio, and the analysis of variance (ANOVA) were employed to analyse the effect of coolant approaches and drilling parameters. The objective was to establish a model using multiple regression analysis between spindle speed, coolant (air) pressure and feed rate with the drill bit temperature. Mathematical models for drill bit temperature are proposed that agree well with the experiments.     

Analysis of temperature changes on the twist drill under different drilling conditions based on Taguchi method during dry drilling of Al 7075-T651

In this work, effects of drilling parameters (drilling depth, feed rate, and spindle speed) on the twist drill bit temperature and thrust force in the dry drilling of Al 7075-T651 material were experimentally investigated. During dry drilling experiments, drill bit temperature and thrust forces were measured. Drill temperatures were measured by inserting standard thermocouples through the coolant (oil) hole of TiN/TiAlN- coated carbide drills. The settings of drilling parameters were determined by using the Taguchi experimental design method. An orthogonal array, the signal-to-noise (S/N) ratio, and the analysis of variance (ANOVA) are employed to analyze the effect of drilling parameters. The objective was to establish a model using multiple regression analysis between spindle speed, drilling depth, feed rate, and drilling method with the drill bit temperature and thrust force in a Al 7075-T651 alloy material. The study shows that the Taguchi method is suitable to solve the problems with a minimum number of trials as compared with a full factorial design .     

加工汽车零部件复杂轴类零件的钻头试验研究

整体硬质合金钻头在带齿的轴上钻深孔时由于切削过程中切削力变化复杂,导致钻头寿命降低,严重时钻头会发生折断。分析实际加工条件的不同特征后,修改原有钻头,设计不同形式的钻头适应不同加工设备。实验表明,新型钻头可延长刀具寿命1.5倍,解决钻头的缠屑等问题,提高了加工效率。     

脉冲磁场处理对硬质合金钻针钻削性能的影响

为提高硬质合金钻针的钻削性能,利用脉冲磁场后处理技术,以0～2T的磁场强度对直径为0.5 mm的硬质合金钻针进行了后处理,对处理后的钻针在印刷电路板上进行了钻孔实验,并分别对钻针的磨损、钻孔质量、微观组织以及力学性能进行了表征。结果表明,在钻削4000和12000个孔后,经过处理后的钻针磨损均显著降低,其中当采用1T工艺时,钻针在钻削4 000个孔后,磨损面积减小了37.97%;而采用2T工艺时,钻针在钻削12 000个孔后,磨损面积减小了38%。经过处理后的钻针钻孔孔径较未处理的钻针波动范围减小,波动范围在0.47～0.5mm之间,而未处理钻针波动范围在0.44～0.49 mm之间,同时1.5T工艺可使孔壁粗糙度减小42%,有效提高孔壁光滑度。脉冲磁处理后钻针的纳米硬度和弹性模量分别提高了26%～116%和40%～312%,且硬度和弹性模量随着脉冲磁场强度的增大而增大。脉冲磁场诱导微观缺陷增殖是钻针钻削及力学性能的提升的主要原因。