回火

Gas welding equipment - Safety devices - Part 2 : not incorporating a flame arrestor.

气焊设备。安全装置。第2部分：不含有回火制止器的安全装置

Gas welding equipment - Safety devices - Part 1 : incorporating a flame arrestor.

气焊设备。安全装置。第1部分：含有回火制止器的安全装置

Flame arrestor is a safety device which shell be used in preventing combustion in pipe Generally F.A.is installed in pipe for running or vent pipe such as torch assembly,heating process furnace, oil gas recovery and other combustiblegas systems.

阻火器是用来阻止易燃气体、液体的火焰蔓延和防止回火而引起爆炸的安全装置。通常在输送或排放易燃易爆气体的储罐和管线上。如火炬、加热燃烧系统、石油气体回收系统或其它易燃气体系统。

This welding wire not only has the inherent properties of metal powder-cored wire, such as with better welding quality, without slag, highly efficiency and conveniently adjusting the alloying elements etc., but also has the advantage of low hardness in as-welded (less than HRC45), good machinability, high hardness in as-aged (more than HRC55) and better wear resistance with customary working procedure on making or repairing equipments such as rollers when reasonable designing the alloys content. The author adequately makes use of the high-tempering in the required stress relieving working procedure. During this working procedure, which causes the hardness of overlaying metal increased by the reason of austenite changes into tempered martensite and more chiefly what is the precipitation of a lot of carbide by secondary hardening simultaneously. This wire can solve the hard rolled problems of some solid wires with higher alloys while it can get over the conflict of existing overlaying materials what are always possesed high hardness with poor machinability or low hardness, good machinability with poor wear resistance. Further, it also can overcome the intenerating phenomena between welding beads and make the external hardness of overlaying metal uniform. Be sure it could be found important meaning in the overlaying of wear-resistant equipments, such as the precise roller.

该焊丝除了具有金属粉型药芯焊丝焊接质量好、无渣、高效率和合金成分可方便调节等固有的优点外，合理的设计粉芯中的合金成分，按通常工序制造与修复轧辊等设备，充分利用必需的消除应力工序的高温回火，堆焊层金属在奥氏体转变为回火马氏体的同时更主要是通过二次硬化析出了大量碳化物导致硬度增加，使得该焊丝还具有焊态硬度低(小于HRC45)、机加工性能好和时效态硬度高(大于HRC55)、耐磨性能好等优点，解决了某些高合金实芯焊丝轧制困难的问题，同时克服了现行堆焊材料硬度高、加工性能差或者硬度低、加工性能好、耐磨性差的矛盾，并能克服焊道之间的软化现象，使堆焊表面硬度较为均匀，对耐磨件，譬如精轧辊的堆焊具有重要意义。

The presence of austenite at any 10% would causeloss of strength of both steels about 10 kg/mm~2, however, their toughness mightbe actually improved by these softer austenites formed along the boundaries oflath martensite.

回火奥氏体的存在使强度下降，估计10％的奥氏体使强度损失约10kg/mm~2。但较软的回火奥氏体沿板条状马氏体边界形成改善钢的韧性，使冲击韧性a_K提高。

Systematic research about technology parameters influences on the magnetic properties and microstructure of theses magnets have been done. The better parameters of production have been achieved. They are showed as follows: as-cast alloys with the nominal composition Nd15Fe78-xNbxB7 are prepared by induction-melting under argon atmosphere. As-cast alloys are broken under argon atmosphere and filtered through 40# screen. The coarse grain is ball-milled under 120# avgas for 80 min. The ratio of milling ball and grain is 15:1. Then fine powder is aligned and pressed in a magnet field of 1.5T. The pressure is 80MPa. The green compacts then are shaped by cold isostatic pressing under 280MPa pressure.

通过研究具体工艺参数对磁体磁性能及显微结构的影响，总结出适合于该系列磁体的制备工艺如下：按设计成分将原料放入真空感应熔炼炉内进行合金铸锭的熔炼；合金铸锭在高纯氩气保护下粗破碎过40目筛；以15∶1的球料比在120#航空汽油的保护下滚动球磨80min；球磨好的磁体粉末在1.5T取向磁场下以80MPa的压力模压成型，接着在280MPa压力下进行冷等静压；所得的压坯在1110℃烧结1h，900℃回火处理1h，600℃回火处理2h。

A layer of strip steel was found abrasion-welded to the surface of the spalled fragment and a 0.06mm thin layer of untempered martensitic structure was observed on the surface of the roll just beneath the welded strip.

在剥落块的表面上粘结着带钢，在带钢下的轧辊表面上观察到一层厚度约0.06mm未经回火的马氏体组织，此层下面还有一个具有低硬度的回火马氏体区域，晶间显微裂纹就从此两区域之间发生，然后垂直地向里向外扩展。

Crack reasons for this are: the heating temperature is too high as a result of quenching or cooling in a hurry, the quality of thermal stress and metal volume changes in the organization of the anti-stress than the breaking strength of steel; the work of the original surface defects (such as surface micro-cracks or scratches) or the internal defect of steel (such as slag, serious non-metallic inclusions, white point, the residual cavity, etc.) formed in the quenching stress concentration; serious Decarburization and carbide surface segregation; parts after quenching Back lack of timely or tempering fire; processes in front of the stress caused by excessive cold red, forging folding, turning deep marks, sharp edges and corners, such as the oil groove.

造成这种裂纹的原因有：由于淬火加热温度过高或冷却太急，热应力和金属质量体积变化时的组织应力大于钢材的抗断裂强度；工作表面的原有缺陷或是钢材内部缺陷（如夹渣、严重的非金属夹杂物、白点、缩孔残余等）在淬火时形成应力集中；严重的表面脱碳和碳化物偏析；零件淬火后回火不足或未及时回火；前面工序造成的冷冲应力过大、锻造折叠、深的车削刀痕、油沟尖锐棱角等。

Coil is the earlier heat treatment enterprises in our province, after more than 10 years of development, the company from an oil-tempered steel pipeline development to the present six, one of which is the introduction of foreign advanced technology of strip lead to hardening Pipeline fire, a domestic leading position in this formed on the basis of a set of their production process, with strong competitiveness.

是我省较早钢带热处理企业，经过十几年的的发展，公司由原来的一条带钢油淬火回火流水线发展到现在的6条，其中一条是引进国外先进工艺的钢带铅淬火回火流水线，处于国内的领先地位，在这基础上形成了一套自己的生产工艺，具有较强的竞争能力。

It 's mainly used in steel tubes of high 's mainly used in steel tubes of high temperature superheaters with surface temperature temperature superheaters with surface temperature ≤625℃ and high ≤625℃ and high temperature reheaters with surface temperature temperature reheaters with surface temperature ≤650℃, and high ≤650℃, and high temperature headers and steam pipes with surface temperature temperature headers and steam pipes with surface temperature ≤600℃.

主要主要用于壁温≤625℃的高温过热器、壁温≤650℃的高温再热器钢管，以及壁温≤600℃的高温集箱温≤625℃的高温过热器、壁温≤650℃的高温再热器钢管，以及壁温≤600℃的高温集箱和蒸汽管道，国内外已逐步用该钢代替和蒸汽管道，国内外已逐步用该钢代替T22、F12、TP304L、TP347H等，但该钢焊接性能T22、F12、TP304L、TP347H等，但该钢焊接性能也比较差，容易产生焊接冷裂纹，所以同样要求有合适的预热温度和及时进行焊后回火处也比较差，容易产生焊接冷裂纹，所以同样要求有合适的预热温度和及时进行焊后回火处理。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷