激光复合处理K24超合金表面残余应力

利用激光冲击技术对经激光淬火形成的K24超合金先进行了复合处理,用X-350A型X射线应力仪测定了激光复合处理区的残余应力,同时分析了复合处理区在500℃回火处理工艺后的残余应力变化规律,并对K24超合金复合处理区疲劳寿命的影响进行了研究。结果表明,激光冲击处理K24超合金淬火区后的残余压应力为600 MPa以上,经500℃回火处理81、6 h后残余应力仍然大于基体的残余压应力,其回火稳定性较好,有利于提高K24超合金的疲劳寿命。     

激光复合处理K24超合金表面残余应力

利用激光冲击技术对经激光淬火形成的K24超合金先进行了复合处理,用X-350A型X射线应力仪测定了激光复合处理区的残余应力,同时分析了复合处理区在500℃回火处理工艺后的残余应力变化规律,并对K24超合金复合处理区疲劳寿命的影响进行了研究。结果表明,激光冲击处理K24超合金淬火区后的残余压应力为600MPa以上,经500℃回火处理8、16h后残余应力仍然大于基体的残余压应力,其回火稳定性较好,有利于提高K24超合金的疲劳寿命。     

提高电火花加工热锻模具疲劳抗力的途径

采用能较好模拟热锻模具加载条件的冲击疲劳试验方法,研究了提高电火花加工热锻模具冲击疲劳抗力的工艺途径.结果表明,采用水基工作液电火花加工,电火花加工后高温回火处理及喷丸强化等措施,都可提高试样的冲击疲劳寿命.文中用试验资料合理解释了上述结果,并提出了改善热锻模具疲劳抗力的工艺途径.     

不同热处理对热模钢H13的组织和性能的影响

本文研究了热模具钢H13（4Cr5MoSiV1)经不同热处理工艺处理后的显微组织和性能，结果表明，H13钢经软氮化处理后，耐磨性，热疲劳抗力较好而冲击韧性较低，250℃等温淬火加回火处理后的冲击韧性最高，热疲劳抗力比政党淬火加回火处理的好，耐磨性较差，300℃等温淬火回火处理的冲吉韧性和疲劳抗力较低，据此，在受冲击载荷情况下，采用250℃等温淬火回火热处理工艺较好，受冲击载荷较小时，采用正常淬火加回火软氮化复合热处理工艺较好。     

深冷处理对双金属带锯条切削性能的影响

应用实验手段研究了深冷处理对双金属机用带锯条切削性能的影响，包括对刃部材料M42钢的红硬性、耐磨性的研究以及对背部材料Rm80钢疲劳性能的分析。结果表明：深冷处理不仅可提高M42钢的红硬性、耐磨性；同时提高了Rm80钢的抗疲劳性能，延长刀具的使用寿命，通过对比回火前和回火后 深冷处理工艺，发现采用回火后 深冷处理工艺能显著提高材料寿命。     

滚子链疲劳寿命威布尔分布形状参数的探讨

探讨了滚子链疲劳寿命的分布规律；揭示了滚子链疲劳寿命威布尔分布形状参数随链条规格、载荷水平变化的特点；设计了可靠寿命和平均寿命的抽样检验方案，从而为滚子链疲劳可靠性设计和验证提供了重要依据     

滚子链疲劳寿命威布尔分布形状参数的探讨

探讨了滚子链疲劳寿命的分布规律，揭示了滚子链疲劳寿命威布尔分布形状参数随链条规格，载荷水平变化的特点，设计了可靠寿命和平均寿命的抽样检验方案，从而为滚子链疲劳可靠性设计和验证提供了重要依据。     

影响滚子链疲劳寿命的主要因素

对链板材料的疲劳强度、链板孔表面加工质量、链板应力集中、整链预拉强化、链板喷丸强化等影响滚子链疲劳寿命的规律进行了深入的研究，给出了提高滚子链疲劳寿命的工艺参数。     

影响滚子链疲劳寿命的主要因素

对链板材料的疲劳强度，链板孔表面加工质量，链板应力集中，整链预拉强化，链板喷丸强化等影响滚子链疲劳寿命的规律进行了深入的研究，给出了提高滚子链疲劳寿命的工艺参数。     

30CrMnSiNi2A钢的回火马氏体脆性——兼论其回火温度的选择

本文研究了超高强度钢30CrMnSiNi2A的回火马氏体脆性(以下简称TME)及与之有关的机械性能,结果表明:该钢TME的表现行为随着加载条件的不同而异。在高速加载条件下,即冲击韧性试验时,TME发生在350～550℃回火温度区间;在低速加载条件下,即静态断裂韧性或冲击疲劳试验时,TME发生在300～400℃回火温度区间。通过在适当温度(200～300℃)回火,可提高其残余奥氏体γ_R的机械稳定性,从而获得良好的强韧化效果。实践证明,在250℃附近回火可获得强度、韧性和冲击疲劳寿命的最佳配合。     

钨铬合金白口铸铁的外约束型热 疲劳特性

为开发钨铬合金白口铸铁轧辊的新型材料，对在外约束条件下的热疲劳行为进行了研究。结果表明：影响其外约束热疲劳抗力的主要因素是屈服温主工和强度，屈服温度越高，屈服强度越大，热疲劳抗力直工大；     

卷制螺旋滚子结构尺寸的理论分析及验证

提出了一种全新理念的滚子——卷制螺旋滚子,并识别出这种卷制螺旋滚子的结构尺寸与变形能之间的关系。这种滚子周身遍布缝隙,能更多地吸收冲击能,可用来解决高速多冲作用下普通滚子耐冲击性能差、易于出现早期断裂失效的问题,并通过疲劳实验和噪声实验验证了卷制螺旋滚子的优越性。     

冲击式压路机治理湿陷性黄土地基的实践研究

通过在宁夏银川至武汉高速公路桃山口至同心段高速公路非自重湿陷性黄土的施工中,采用了冲击式压路机法消除了黄土的湿陷性,提高了地基承载力,并取得了大量的试验数据.文章根据对施工后非自重湿陷性黄土地基的检测、评价和理论分析,总结了冲击式压路机法处理非自重湿陷性黄土地基需要控制的指标:①采用25 kJ冲击式压路机进行冲击施工时,冲击碾压遍数以40遍为宜,控制深度为0～90 cm,压实度应>90％;②平均沉降量应>25 cm,平均孔隙比应<0.55,0～200 cm黄土湿陷性基本消除.该试验结果已在同心至固原高速公路117 km,计2 227 211 m2非自重湿陷性黄土地基的施工中得到广泛的应用,取得了良好的效果.     

用预拉强化工艺提高双排滚子链疲劳性能的研究

为了改善国产双排链的耐疲劳性能和链长精度的均匀性,本文研究了预拉工艺的效果。对08B双排链的试验结果表明,经(2/3)Q(Q为链条极限拉伸载荷)预拉后的链条、链长精度均匀性明显改善;疲劳强度可提高80％左右。预拉后的链条的残余伸长量不大,完全可预先对链板冲模具节距尺寸作适当的调整,以保证链长精度。可以认为,预拉处理对多排滚子链是一种十分必要的强化工艺。     

Failure analysis used for remanufacturing of steel rolling components

The guide-pieces, used in the process line of steel roiling, were the important components. The guidepieces, which were slide contacting with the rolled-piece, had a high temperature and high speed. The wear was very serious. The results from failure analysis showed that there were three failure forms in the guide-pieces: the first was the wear during heat friction, the second was the heat fatigue under the cycle of deep heating and deep cooling, and the third was the impact rupture. Among them, the wear was the main reason. To the wear of guidepieces, there were four mechanisms, namely abrasive wear, adhesive wear, fatigue wear and corrosion wear. The failure analysis to the guide-piece laid the foundation for its remanufacturing.     

Failure analysis used for remanufacturing of steel rolling components

The guide-pieces, used in the process line of steel rolling, were the important components. The guidepieces, which were slide contacting with the rolled-piece, had a high temperature and high speed. The wear was very serious. The results from failure analysis showed that there were three failure forms in the guide-pieces: the first was the wear during heat friction, the second was the heat fatigue under the cycle of deep heating and deep cooling, and the third was the impact rupture. Among them, the wear was the main reason. To the wear of guidepieces, there were four mechanisms, namely abrasive wear, adhesive wear, fatigue wear and corrosion wear. The failure analysis to the guide-piece laid the foundation for its remanufacturing. Foundation item: Project(50235030) supported by the National Natural Science Foundation of China     

深井延迟长脉冲燃爆压裂火药优配与评价

针对燃爆压裂火药爆燃加载速率快、措施安全与裂缝规模难以平衡的问题,基于对成熟火箭推进剂配方的深入考察,借助密闭爆发器、燃速测试仪、落锤仪、摩擦感度仪和差热分析仪等实验设备,筛选优化了延迟长脉冲燃爆压裂火药配方,测试并得到了其从低压到高压的燃速图版,评价了其爆燃加载特性.结果表明,相对传统燃爆压裂火药,该延迟长脉冲火药燃速更低、持压时间更长,且具有较强的耐撞击、摩擦和高温性能,适用于深层、超高压地层油气井.在20℃下测试,延迟长脉冲火药在7 MPa下爆燃加载持压时间78.1ms,为传统燃爆火药的2.12倍;45~70MPa超高压环境下燃速36.4~39.5mm/s,低于传统燃爆火药燃速一半,可有效提高燃爆压裂火药最大装药量、扩大裂缝延伸长度和破裂规模.     

Material analysis of the fatigue mechanism of rollers in tapered roller bearings

Rolling contact fatigue is the main failure mechanism of tapered roller bearings. This study investigated the fatigue mechanism of rollers in a tapered roller bearing that failed in a run-to-failure test. Roller microstructure and crack morphology were investigated through scanning electron microscopy. A microhardness test was performed to investigate the strain hardening of the roller material induced by rolling contact fatigue. Results showed that microcavities and holes are important influential factors of crack initiation and propagation. Crack propagation angle affects crack morphology and propagation mode. Material strain hardening accelerates crack growth. Furthermore, roller misalignment causes uneven hardenability and severe damage to roller ends.     

Influence of Impact Energy on Impact Corrosion-abrasion of High Manganese Steel

The impact corrosion-abrasion properties and mechanism of high manganese steel were investigated under different impact energies. The result shows that the wearability of the steel decreases with the increase of the impact energy. The dominant failure mechanism at a lower impact energy is the rupture of extrusion edge along root and a slight shallow-layer spalling. It transforms to shallow-layer fatigue flaking along with serious corrosion-abrasion when the impact energy is increased, and finally changes to bulk flaking of hardened laver caused by deeo work-hardening and heaw corrosion-abrasion.