澳洲阿德莱德代写assignment:环境保护的温度和压力

Technological advancements have driven up temperature and pressure serviced in the petroleum, chemical, pulp, and environmental protection. Industries, and increased the possibility of severe corrosion and wear in process pressure vessels. The industries must upgrade the corrosion and wear performance of these main important parts .Economic features as a rule will not allow fabricating components from solid high alloyed materials. As a result it is essential to surface non-alloyed or low alloy base materials with high-alloy cladding. The submerged arc welding(SAW) and electroslag welding (ESW) process are appropriate for applying welded deposits over large surface areas by means of strip electrodes .Both processes are using a granular flux material. A strip electrode, fed continuously, is liquefied and fused to the substrate. In contrast with other processes it is very effective in spite of the same equipments used but due to the wide strip used it procures a magnetic flow effect within to rectify it a magnetic steering device is exercised. After the welding to examine the defects NDT's are carried upon it. Electro slag strip cladding is an advancement of submerged arc strip cladding, which has speedily established itself as a reliable high deposition rate procedure. ESW is an arc less technique using Joules Effect to liquefy the strip material. The heating is an outcome of current flowing through the strip electrode and a relatively shallow layer of liquid electro conductive slag as shown in figure 1. The penetration is lesser for ESW than for SAW since the molten slag pool is used to liquefy the strip and some of the flux material rather than as an arc between the strip electrode and the flux material. As a rule of thumb, electro slag strip surfacing decreases dilution by up to 50% in contrast with submerged arc strip surfacing for the same heat input with a significantly higher deposition rate. However, as a consequence of the lower dilution levels for ESW, new strip compositions have been built for ESW, in particular for applications where the purpose is to obtain a certain weld metal chemistry (such as 304L, 316L) in one layer.