共查询到20条相似文献,搜索用时 250 毫秒
1.
分析了球形顶头轧管工艺,介绍了轧辊孔型设计和轧机调整方法。球形顶头和锥形顶头轧管质量比较表明,球形顶头轧管有利于提高毛管尺寸精度。 相似文献
2.
3.
4.
5.
研究了热处理工艺和化学成分对轧管机顶头组织的影响,从而得出最佳热处理工艺和最佳化学成分,为今后提高轧管机顶头的使用寿命提供了依据。 相似文献
6.
穿孔不锈钢管用钼合金顶头的研制和应用 总被引:1,自引:0,他引:1
介绍了变形态钼合金穿管顶头的研制及其工艺技术。在生产上应用该顶头穿孔1Cr18Ni9Ti管获得成功,试验表明,与玻璃润滑剂配合使用可取得更佳效果,还可改善钢管内外表面质量。 相似文献
7.
8.
9.
10.
提高穿孔砂使用寿命的研究 总被引:1,自引:0,他引:1
分析了无缝这穿孔顶头的失效机制和材质改进状况,穿孔顶头的失效机制主要表现为塌鼻、粘钢和开裂等。经对H13负穿孔顶头进行稀土铝合金化的实验研究。结果表明,稀土铝合金化可以明显地改善H13钢穿孔顶头的铸造性能,消除中心缩孔现象,细化晶粒和碳化物,降低S、P含量。穿管试验表明,H13钢稀土铝合金化穿孔顶头的使用寿命比H13钢穿孔顶头提高了40%。 相似文献
12.
在调查国内一些Ф76~100mm机组内水冷穿孔顶头使用情况的基础上,分析了该类顶头的失效形式及其原因,从顶头冷却问题入手,相应改进了内水冷穿孔顶头的内孔设计,冷却水的压力和进水与回水之配比。改进的内水冷顶头使用寿命大为提高。 相似文献
13.
小六角火花塞是当前汽车发动机上普遍采用的点火元件,分析小六角火花塞与传统火花塞的主要区别,介绍小六角火花塞壳体成形工艺的特点,探讨小六角火花塞的材料选择、下料、毛坯精整形、退火、润滑处理和冷挤压工艺,同时,也介绍了这种壳体成形工艺过程中容易出现问题的工序、部位和解决方法.最后还对形状复杂、独特的小型冷挤压零件的成形要点和不足之处进行了总结. 相似文献
14.
论述了保温炉内通过透气塞对铝液进行精炼净化,去除杂质的方法,重点论述了透气塞精炼的优点、透气塞在保温炉内的分布状况,并对实际除氢效果进行了分析。对于85t矩形保温炉,采用18个透气塞精炼时,除氢效率能够达到30%~40%。通过优化透气塞在保温炉内的分布,改善透气塞与周围耐火材料的兼容性,能够显著提高除氢精炼的效果。 相似文献
15.
16.
17.
底吹电弧炉熔池混合过程的模拟研究 总被引:3,自引:0,他引:3
实验测量了电弧炉底部单喷嘴和多喷嘴喷吹的熔池水模型中混合时间和若干断面流场、混合时间随喷嘴直径、数量、位置及示踪剂投放点变化的函数关系。通过数值法求解了熔池流场及其混合过程。结果表明,仅靠增加喷嘴直径来改进熔池搅拌效果不显著。偏心、深熔池处布置的多喷嘴喷吹的流场混合能力较强,原因是这样布置使熔池流场具有较强烈的圆周方向对流并能获得更多的搅拌功率。 相似文献
18.
19.
《Science & Technology of Welding & Joining》2013,18(4):259-266
Underwater friction taper plug welding for X65 pipeline steel was performed using Q345 structural steel and 316L stainless steel plugs. Weld microstructures, defects formation and mechanical properties were investigated. Using Q345 plugs can produce defect free and overmatching welded joints whose impact toughness was also favourable. Lower bainite and lath martensite in the weld zone resulted in high hardness with maximum value up to 418?HV10. Using 316L plugs can significantly reduce weld zone hardness due to austenite dominated microstructure. Microcracks can easily emerge at and may propagate along γ–δ phase boundaries to form macrocracks. Intermittent cracks were found along the bonding interface of all the 316L plug welds, which should be caused by the relief of the residual stress. 相似文献
20.
Summary This paper describes a residual stress relief method for butt welded joints in pipework made using ice plugs. Named by the authors the Twin Ice Plug (TIP) method, it is basically as follows. Two ice plugs are formed inside the pipework and isolate a section including a welded joint. The internal pressure of the isolated section increases as the ice plugs grow, imparting tensile strain to the pipe wall of the section. When the pressure reaches the target level, it is released, and the residual stress decreases. The paper describes details of this process, measurement of the internal pressure outside the pipework, control of the internal pressure, and the effect of residual stress relief. The internal pressure of the isolated section is estimated by the strain measured by strain‐gauges affixed to the outside surface of the section. Section pressure control is exercised by control of refrigerant (liquid nitrogen) supply and pipe wall heating. The maximum internal pressure attained by this method is 40 MPa for 4BSch40 (OD. = 114.3 mm, t = 6.0 mm) stainless steel pipe and 22.5 MPa for 6BSch40 (OD = 165.2 mm, t = 7.1 mm) pipe. The residual stress of GTA welds in stainless steel pipe is measured, its maximum value being more than] 300 MPa. The effects of the proposed method are confirmed by measurement of the residual stress of TIP‐treated 4BSch40 and 6BSch40 joints. The residual stress of the inside surface decreases and changes to compression, and that of the outside surface also decreases to less than 100 MPa. 相似文献