工程液压油缸关键焊缝焊接工艺技术研究

液压缸缸筒与缸头、缸筒与油口的焊接部位是液压缸漏油的最频发部位,其焊缝质量是关系液压油缸成品率,液压油缸质量、性能的关键因素,焊接不良时会导致焊缝处的漏油,严重影响整机性能,甚至造成严重事故。对其进行返修补焊,又费时费力,大大降低了液压缸生产效率。针对油缸复杂焊缝焊接机理和工艺过程进行了研究,提出了新的工艺路线和焊接方案,并制定了焊接工艺规范,取得了非常显著的效果。     

缸筒与耳轴的配合间隙对焊接变形的影响

缸筒与耳轴的焊接式连接有诸多优点,但也避不开常见的焊接变形问题.文章根据企业自身的生产环境,探索粗镗缸筒与耳轴的配合间隙对缸筒内孔焊后变形的工艺研究方法及影响,从中找出其焊接变形的规律,为油缸设计、粗镗缸筒的备料和生产工艺提供依据.     

20MnTiB缸体用无缝钢管研制开发

介绍了20MnTiB缸体用无缝钢管的生产工艺和质量情况，以转炉炼钢＋LF精炼＋340连轧管机组生产的20MnTiB厚壁无缝钢管完全满足制造工程机械液压油缸的钢质、力学性能和尺寸精度等要求，其综合性能优于27SiMn钢管。     

原始组织对690 MPa级海工钢亚温淬火后强韧性的影响

 为了稳定亚温淬火工艺与工业化生产,通过力学性能分析及显微组织观察,对比了正火+亚温淬火+回火、在线淬火+亚温淬火+回火、离线淬火+亚温淬火+回火3种热处理工艺对690 MPa级海洋工程用钢板组织性能的影响。结果表明,采用离线淬火+亚温淬火+回火工艺结果最理想,能够大幅度提高钢板的低温冲击性能和伸长率。同时,还能够获得较低的屈强比,断口形貌全部为韧窝,呈明显的韧性断裂,而且随着亚温保温时间的增加,强度逐渐提高,当保温时间达到30 min以后,强度及条片状铁素体基本不发生变化;采用直接淬火态+亚温淬火+回火虽然可以保证高强度低屈强比,但是冲击功表现较为离散,稳定性欠佳,断口形貌为混合型,以韧性断裂为主;采用正火态+亚温淬火+回火工艺效果最差,尤其是不能保证钢板低温韧性,断口形貌全部为解理,呈明显的脆性断裂,其中片条状铁素体形貌是决定优良低温冲击性能的关键因素。     

1Cr17Ni2钢的高温回火脆性

研究了亚温淬火对１Ｃｒ１７Ｎｉ２钢高温回火脆性的影响。结果表明，亚温淬火能有效地抑制该钢的高温回火脆性。经亚温淬火后，钢的脆性转化温度降低，韧性得到改善，断口形貌由准解理型变为韧窝型，合金元素向基体和δ铁素体中的富集程度增大，在改善钢的韧性的同时仍保持较高的强度水平。     

27SiMn厚壁无缝钢管热处理工艺研究

针对27SiMn的厚壁无缝钢管淬透性较差,热处理后钢管性能稳定性较差,两端差异性较大,强度、硬度匹配性较差等问题,通过调整淬火温度、淬火保温时间,回火温度及保温时间,可以改善产品的状态,提高了产品强度,降低了硬度。     

预备热处理对A-F区亚温淬火-回火的42CrMo钢组织和性能的影响

利用金相显微镜、洛氏硬度计和扫描电镜,对经过预备热处理(退火、淬火、调质)+亚温淬火+高温回火处理(又称临界区淬火+回火)后的42CrMo钢的组织、冲击性能以及断口形貌进行了观察和分析。结果表明,预备热处理为退火处理时,亚温处理后残留的铁素体粗大不均;且在回火索氏体之间分布不均匀;预备热处理为淬火处理和调质处理时,残留的铁素体形态细小,且与回火索氏体均匀分布。采用不同预备热处理时,亚温处理后的硬度差别很小。亚温处理后42CrMo钢的冲击性能均高于常规调质处理后的冲击性能;预备热处理为调质处理时,亚温处理后的冲击功最大,从其断口形貌中可以看出,其起裂区和裂纹纤维扩展区所占比例较退火处理和淬火处理时要大。因此,调质处理更适合作为42CrMo钢的预备处理。     

双液压缸模拟加载试验回路分析

１双缸加载回路基本原理为了对油缸进行性能试验，需用加载回路通过加载缸对被试缸进行加载。这种采用一台油缸对另一台油缸用机械联接进行加载的试验方法，要求油缸台架具有足够的强度和刚度，要占用很大的空间，试验装置的加工制造费用很高，一般非专业试验室不具备这种...     

45号钢调质后亚温淬火的效果

介绍了45号钢调质后进行亚温淬火所取得的效果，提高了韧性，延长了备件使用寿命。     

27SiMn液压支架管的试制

文章介绍了27SiMn的技术条件、冶炼工艺、精炼工艺、连铸工艺以及轧制工艺，研究了合适的热处理工艺，最终得到了性能合格的27SiMn无缝管。     

耦合孪生晶体塑性模型硬化参数的灵敏度分析

基于经典晶体塑性理论,建立了耦合孪生的晶体塑性本构模型并进行了全隐式积分的数值实现.该本构模型采用饱和硬化法则,并采用孪生阻力与滑移硬化之间的正比关系来描述孪生对滑移硬化影响及孪生硬化行为.针对该本构模型的13个参数,结合各参数物理意义提出了参数的分类确定方法.以孪生诱导塑性（TWIP）钢Fe-22Mn-0.6C为例,着重对硬化参数的局部灵敏度进行了分析,研究了各硬化参数对宏观力学响应、孪生激活和演化的影响,根据变形机制的不同宏观变形过程可区分为孪生硬化阶段和孪生硬化失效阶段,进而给出了硬化参数确定的步骤及其建议取值范围.结果表明:初始滑移阻力与屈服极限线性相关,取值范围在80~160 MPa之间;孪生硬化指数增大使得孪生硬化阶段减弱,其取值范围应在0~3之间;孪生阻力与滑移阻力比值增大,则孪生增长率降低,硬化率拐点后移,直至拐点消失,其取值范围在1~1.3之间.      

铁索体/贝氏体多相组织钢硬化行为表征参数

摘要：为了研究大变形管线钢应变硬化行为及其表征参数之间关联性，采用TMCP工艺调控制备了9种不同贝氏体体积分数的铁素体/贝氏体（F/B）多相组织钢。通过力学性能及应变硬化行为分析，对应变硬化指数、应力比、屈强比和伸长率等大变形管线钢应变硬化能力表征参数之间的关联性及其机制、内涵和适用范围进行了研究。结果表明，F/B多相钢中，应力比Rt20/Rt10和均匀伸长率与应变硬化指数呈线性正比关系，屈强比与应变硬化指数呈非线性反比关系，应力比Rt50/Rt10在一定条件下与应变硬化指数存在线性关系，应力比Rt15/Rt05、总伸长率、应变硬化指数之间不具备明显的关系。通过应变硬化行为分析合理阐释了以上参数之间的关联机制，并阐释了其内涵和适用范围。硬化指数、均匀伸长率和应力比Rt20/Rt10应作为描述F/B多相钢塑性形变阶段应变硬化能力的主要参数，屈强比和应力比Rt50/Rt10则应作为次要参数。采用工业化生产数据对上述结论进行了验证，与所得结论吻合良好。     

Solid-solution hardening of a high-Entropy AlTiVCrNbMo alloy

The nature of solid-solution hardening of high-entropy alloys is discussed using an equiatomic bcc AlTiVCrNbMo alloy as an example. The hardening of the alloy is found to be characterized by an increase in the temperature dependence of the component of the critical shear strength and by anomalously high athermic hardening due to the perpendicular slip plane of the Burgers vector component. A relatively simple expression is proposed to estimate the detected hardening ΔH(Δσ).     

Hardening mechanisms and deformation stages in nanograined polycrystals

Strain hardening of nanograined polycrystals is studied using copper-based alloys as an example. The stages of strain hardening are compared for these alloys and for pure metals (copper, gold) having a similar grain size in the range 40–200 nm. The stress σ-strain ɛ dependence demonstrates that the strain hardening of these polycrystalline nanograined materials proceeds, as a rule, in three stages with different hardening mechanisms.     

An exponential hardening model for anisotropic sheet metals

A new exponential hardening rule is brought forward to apply for planar anisotropy strain‐hardening sheet metals. Three exponential hardening relations measured along the rolling direction, 45°‐angle and 90°‐angle direction against rolling direction are just the special cases of this model. Based on this model to solve some plastic deformation problems for anisotropic strain‐hardening materials, some functions and calculating results, such as constitutive relations, forming limit characteristic, springback and other parameters associated with these types of materials, should be more likely to approach real states. So this anisotropic strain‐hardening model is very important for applying sheet metal forming simulation.     

Effect of shock-wave treatment on the structure and hardening of austenitic steels

The structure and hardening of austenitic steels subjected to shock-wave treatment have been studied. This treatment is shown to form a structure whose cell size decreases with increasing pressure. The treatment-induced hardening of the steels can be estimated using the Hall-Petch relation. At the same degrees of residual deformation, shock-wave treatment results in a significantly higher degree of hardening of the austenitic steels as compared to cold rolling. The degree of hardening increases with decreasing stacking-fault energy in austenite.     

激光硬化表面处理技术及其应用现状

介绍了激光硬化技术三种工艺即激光相变硬化、激光熔凝硬化和激光冲击硬化的特点,概述了激光硬化技术的应用现状.     

Parameters Optimization of Plasma Hardening Process Using Genetic Algorithm and Neural Network

 Plasma surface hardening process was performed to improve the performance of the AISI 1045 carbon steel. Experiments were carried out to characterize the hardening qualities. A predicting and optimizing model using genetic algorithm-back propagation neural network (GA-BP) was developed based on the experimental results. The non-linear relationship between properties of hardening layers and process parameters was established. The results show that the GA-BP predicting model is reliable since prediction results are in rather good agreement with measured results. The optimal properties of the hardened layer were deduced from GA. And through multi optimizations, the optimum comprehensive performances of the hardened layer were as follows: plasma arc current is 90 A, hardening speed is 22 m/min, plasma gas flow rate is 60 L/min and hardening distance is 43 mm. It concludes that GA-BP mode developed in this study provides a promising method for plasma hardening parameters prediction and optimization.