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本文论述了冶轧工艺对中空钢的性能及其制成钎杆凿岩寿命的影响。结合钎杆凿岩过程中的工作应力,分析了钎杆内外疲劳源点的产生、扩展及瞬间破断的情况。通过比较四种冶轧工艺的钎钢性能及其凿岩寿命,指出了缩孔夹杂、脱碳、晶粒粗化等冶金缺陷,是改善钎钢性能和提高钎杆凿岩寿命必须注意的问题。此外,提高中空钢锭、坯、材的内外表面质量是消除钎杆内外疲劳源点产生,避免钎杆早期断裂,稳定凿岩寿命的关键途径。 相似文献
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根据离散元相关理论, 利用EDEM软件对高铟高锡银基钎料粉末电磁压制过程进行仿真模拟, 探究工艺参数对Ag–Cu–Sn–In系钎料压制过程中的影响规律, 分析钎料粉末的致密化行为, 并研究Sn元素和In元素对钎料粉末相对密度的影响; 在不同电压和电容条件下, 对Ag–19.5Cu–15In–15Sn钎料粉末压制过程进行了仿真模拟, 分析不同放电参数对压坯相对密度的影响; 最后通过压制设备制备钎料压坯, 对仿真结果进行验证。结果表明, 在相同压制力下, In质量分数越高, 获得的压坯相对密度越大; 在电容相同的情况下, 电压越大压坯的相对密度越大, 但增幅逐渐减缓; 在电压相同的情况下, 电容越大压坯的相对密度越大, 但增幅大致不变。实验验证结果表明, 仿真误差小于8%, 钎料电磁压制离散元仿真模型具有一定的参考价值。 相似文献
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介绍了粉状铝基钎料的制备方法,探讨了粉状铝基钎料的工艺性能。从表面张力的角度出发,讨论了粉末粒度、氧含量、加热速度、加热均匀性、钎料钎剂比例等因素对高频铝材钎焊工艺和性能的影响。结果表明:用粒度在150~180μm的粉状铝基钎料钎焊铝材,其钎焊剪切强度较高;加热速度较快、加热盘温度均匀的钎焊效果较好;钎料钎剂的比值在10∶8~10∶10范围钎焊效果较好。 相似文献
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42CrMo钢Φ180 mm热轧圆钢制造的破碎锤钎杆,某客户在使用不久便产生钎杆锥头纵向劈裂现象。经对劈裂钎杆进行断口形貌、金相组织等理化分析。结果表明:钎杆锥头纵向劈裂属于疲劳断裂,引起疲劳断裂的主要因素是钎杆心部存在沿纵向贯通性裂纹,而贯通性裂纹则来源于原材料圆钢,其原因是连铸坯中心缩孔在轧制时未能完全轧合有关。通过试验方案改善连铸坯内部质量,优化轧制工艺,完善入坑缓冷制度,最终解决大规格圆钢心部裂纹的质量问题。 相似文献
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介绍一种球状NiP11钎料在模具内熔化成形的制作工艺。通过对模具材料和熔化温度等工艺参数的对比试验和分析得出:选用氧化铝质坩埚陶瓷材料作模具,能保证球状NiP钎料的尺寸稳定性、表面光洁度、球形度,并有较高的成品率;熔化温度宜控制在895℃左右。 相似文献
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我国钎钢钎具工业生产现状及发展趋势 总被引:6,自引:1,他引:5
概述了我国钎钢钎具(包括中空钢材,冲击式凿岩钎杆和硬质合金凿岩钎头)工业生产现状及发展趋势,分析结果得出,我国钎钢钎具工业应加强整体钎杆、凿岩钻车用钎杆和潜孔钻具的生产与研制工作。 相似文献
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异型坯结晶器喂稀土丝试验研究 总被引:1,自引:0,他引:1
在SS400钢中进行了异型坯结晶器喂稀土丝工业试验,结果表明:稀土在异型坯的分布较均匀,稀土回收率为81.9%~87.1%,硫化物球化良好,提高了H型钢的低温冲击功。 相似文献
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传统理论认为,脱壳挤压是利用比铜锭外径小的挤压垫,利用塑性剪切变形将铜锭外皮脱掉,因此脱壳挤压过程外表面质量不会影响挤压管坯的尺寸,但笔者通过对挤压完毕后挤压筒内剩余铜皮和闷锭时铜皮形状进行观察,发现挤压筒内脱掉铜皮长度与挤压铜锭长度无线性关系,进而提出紫铜脱壳的行为机理,并进行分析得出,脱壳挤压不是绝对的脱壳挤压结论。 相似文献
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应用铸坯在凝固过程中的热应力模型,对水平连铸坯进行了传热、应力和应米的计算分析,表明铸坯出结晶器后温度回升太大和凝固末期中心温度的迅速下降,是产生中心裂纹和中间裂纹的可能原因。 相似文献
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《钢铁冶炼》2013,40(8):582-589
AbstractTwo-dimensional thermo–elastic–plastic creep finite element models of two beam blank moulds with different water slot designs, the large hole mould and the small hole mould, are set up and their thermomechanical behaviour is numerically investigated by means of ABAQUS software. The temperature, distortion, stress and inelastic strain range across the hot faces as well as the fatigue life of the two moulds are discussed in detail, based on which it is shown that the distributions of temperature and distortion of the small hole mould are more uniform than those of the large hole mould, and the peak temperature of the former mould is smaller than that of the later mould. However, the fatigue life of the small hole mould is shorter than that of the large hole mould. Both moulds were put into service in an industry and it is demonstrated that the quality of the product cast by the small hole mould is better than that by the large hole mould, and the service life of the small hole mould is longer than that of the large hole mould because the service life of a mould chiefly depends on the wear of its hot face, which is much shorter than the fatigue life. An improved water slot design for the beam blank mould is then proposed and it is numerically demonstrated that this improved mould is superior to the large hole mould and the small hole mould. 相似文献
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连续挤压包覆技术是在连续挤压技术基础上发展起来的一种新型塑料加工技术,坯料在摩擦力作用下被挤压轮拽入并随其旋转和变形,压入模腔并与模腔中的钢芯复合得到复合材。挤压轮的工作温度为200~250℃,轮槽表面最高温度达590℃。文中叙述了挤压轮的工作条件、主要失效形式、挤压轮用钢的基本性能要求以及国内外挤压轮用钢的化学成分、研究进展和发展趋势。 相似文献
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Conclusions A study has been made of the character of the redistribution of volumes of a porous blank during hot forging with elements of extrusion; the feasibility is shown of controlling the process with the aim of ensuring that certain volumes of material occupy the required positions. It has been confirmed by experiment that the process of hot forging of porous materials with elements of extrusion involves more than one stage. The character of pressing pressure variation in various stages has been determined. In pressing in conical dies densification of central volumes of material lags slightly behind that of peripheral regions. For specimens of the geometric parameters investigated, the width of the peripheral blank zone, which in the steady-state extrusion stages moves parallel to the compressing part of the die, is (0.15–0.20)Dc. The degree of deformation and the redistribution of volumes of material in peripheral layers are affected mainly by the temperature conditions of the pressing process and to a much smaller extent by the starting blank porosity.Translated from Poroshkovaya Metallurgiya, No. 6(282), pp. 15–19, June, 1986. 相似文献