本文分析了气门挺杆端面气孔、裂纹形成原因。
The reason of the formation of gas porosities and cracks on the head face of valve tappet has been studied.
评述了连铸坯内裂纹形成条件的研究方法和结果。
The method and results of the study on formation condition for internal crack in continuous casting slab were reviewed.
介绍了复杂载荷下疲劳裂纹形成寿命预测的方法。
The methods of fatigue crack initiation life predictions under complex load are introduced in this paper.
本文提出一种零部件的裂纹形成寿命的类比估算方法。
A method for crack initiation life prediction of components is presented.
裂纹形成后垂直于加载轴方向扩展，试样呈穿晶断裂。
Once initiated, cracks would propagate perpendicularly to the loading direction and the specimens exhibited transgranular fracture.
压圈原材料中心疏松及锭型偏析是导致裂纹形成的主要原因。
The results showed that central porosity and ingot shape segregate were the major causes of the cracking.
结果表明，堆焊层与基体的界面缺陷是裂纹形成的主要原因。
The results showed that the forming of crack was mostly made by the interface defect between overlaying welding layer and matrix.
高ra值是张裂纹形成产生的波，低值是剪切裂纹形成的波。
High ra value is wave generated by tensile cracks and low ra value is wave generated by shear cracks propagation.
裂纹形成的断裂为穿晶解理机制，预应变可导致更多的二次裂纹。
The fractography of the fatigue crack initiation displayed cleavage facet and more second cracks after pre-training.
研究了稀土变质及热处理对低铬耐磨铸铁热疲劳裂纹形成的影响。
The effect of re modification and heat treatment on formation of thermal fatigue crack in low chromium wear-resistant cast iron was investigated.
证明了用静应力场分析动载下接触疲劳裂纹形成与扩展的可靠性；
Static stress field can be reliably applied to analyse initiation and extension of contact fatigue cracks under motive load.
在低温解理断裂的物理模型中，最重要的是确定解理裂纹形成中的临界事件。
In low temperature cleavage physical model, it is of Paramount importance to ascertain the nature of the critical event in the formation of a cleavage crack.
结果表明，失效形貌呈典型的接触疲劳特征，两种疲劳裂纹形成模式同时存在。
The results showed that failure morphology was of typical contact fatigue characteristics, and two modes of fatigue crack formation worked.
目前大量研究表明，金属材料在裂纹形成过程中，表面会发射大量的低能电子。
At present a large number of researches indicate that the surface of metal material while the crack forms, can be emitted massive low energy electrons.
机械零（构）件的寿命由裂纹形成时间（即疲劳寿命）和裂纹扩展寿命两部分组成。
The whole life of an equipment part consists of the crack forming life (i. e. , the fatigue life or the damage accumulation life) and the crack extension life.
实验还观察到砂岩表面微缺陷发生闭合的全过程，在冷却过程也有微裂纹形成等现象。
Also a closing course of initial crack and thermal cracking coming into being in the cooling process are observed in our experiment.
此外，还定性分析了淬火、回火后残余应力的性质及热处理工艺过程对裂纹形成的影响。
In additions the paper qualitatively analyses the influence of residual stresses occurring after quenching and tempering and the process of heat treatment on the formation of the cracks.
采用此方法确定疲劳缺口系数，获得的损伤参量与裂纹形成寿命关系的数据分散带最窄。
If the plastoelastic fatigue notch factor was regarded as the transforming factor of damage calculation, the data scattering zone of life curve was most narrow.
疲劳过程中主裂纹的形成消耗了大部分的疲劳寿命，一旦主裂纹形成就快速扩展瞬间断裂。
During the fatigue process, the formation of the main crack expends most of the whole fatigue life, and once the main crack forms, the crack propagates rapidly and fractures immediately.
基于断裂动力学理论，文章论述了切缝药包定向断裂控制爆破炮孔间贯通裂纹形成的机理。
Based on the theory of dynamic fracture mechanics, the mechanism of crack-forming among shot holes in the directional split of rock by controlled blasting is expounded.
对含有35 %WC的钢结硬质合金在热应力作用下热疲劳裂纹形成过程进行了反复观察。
Thermal fatigue crack forming process of steel bonded carbide containing 35% WC by the action of thermal stress has been observed time and time again.
结果表明：加入微量镁，不仅能延长合金的蠕变裂纹形成寿命，而且能提高合金的蠕变韧性。
The results show that addition of small amounts of Mg can not only notably increase the creep crack growth life but also increase creep toughness.
特别是运输机谱中的地—空—地循环，在裂纹扩展的公式中对裂纹形成寿命的贡献估计不足。
Especially the contribution to crack initiation life of the ground-air-ground circle in the crack growth formula is underestimated under the transport spectra.
通过对结构疲劳裂纹形成寿命和裂纹扩展寿命的研究，提出了连接件疲劳全寿命的计算方法。
A calculating method of the total fatigue life of structural joints is proposed based on a study on both the fatigue crack initiation life and crack growth life of joints.
着重温度对气门材料的力学性能、蠕变和疲劳裂纹形成与扩张的影响等问题进行分析和研究。
The study work is focused on the effect of temperature upon mechanical properties, creep, initiation and propagation of fatigue crack for the valve material.
同时，稀土使合金的热裂纹形成温度降低，增加了热裂纹形成应力，降低了合金的热裂倾向性。
Moreover, they are able to decrease the temperature and increase the stress of hot cracking formation, as a result, decrease the tendency of hot cracking.
对于不同应力水平作用下的循环时间可计时累加并再现，可为疲劳裂纹形成寿命的预测提供依据。
The circle time under different stress level is accumulated and can be reappeared, so that the basis data is provided to predict surface fatigue crack forming life.
预应变可以延长疲劳裂纹形成寿命，提高疲劳裂纹形成的抗力系数和裂纹形成的当量应力门槛值；
The pre-straining prolonged the fatigue crack initiation life, and increased resistance coefficient and equivalent stress threshold of the fatigue crack initiation.
由于铸坯表面裂纹形成的裂纹灶，降低了产生内裂所需要的应力值，易于形成内、外相连的纵裂。
The stress required for producing internal crack decreases since there are loci of cracks in the slab caused by the surface crack, so the longitudinal cracks from inner to surface form easily.
由于铸坯表面裂纹形成的裂纹灶，降低了产生内裂所需要的应力值，易于形成内、外相连的纵裂。
The stress required for producing internal crack decreases since there are loci of cracks in the slab caused by the surface crack, so the longitudinal cracks from inner to surface form easily.
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