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The stirring assisted brazing of SiCp/A356 composites with a large size of diameter in air was investigated. A first stirring was applied in brazing of the composites at 470°C. Then, it was continuously heated up to 510°C. Then, a secondary stirring with a large size (2.4mm) diameter was introduced in process. It was found that a composite joint reinforced with SiC particles can be obtained by stirring at 510°C. The experiment result shows that micro-hardness of joint brazed by 2nd stirring is obviously higher than that of joint brazed without 2nd stirring. Moreover, micro-hardness of the upper part of joint is slightly higher than that of the bottom part.

The amount of CO2 emissions from steelworks accounts for a great share of the total CO2 emissions from industry in China. Thus, reducing CO2 emissions from steelworks is urgent for China’s environmental protection and sustainable development. This study aims at identifying factors that influence CO2 emissions from steelworks and proposing measures to reduce CO2 emissions. The life cycle inventory (LCI) of iron and steel products implies the relationship between the CO2 emissions of the steelworks and the input variables of the LCI. The Tornado Chart Tool is utilized to calculate the variation of CO2 emissions caused by the change of each input variables of LCI. Then, mean sensitivity of each input variable is calculated and the ranking criterion developed is used to identify the main factors influencing the integrated steelworks. Subsequently, measures for reducing CO2 emissions are proposed. The results indicate that the very important influencing factors of CO2 emissions in steelworks are the CO2 emission factor of Blast Furnace Gas (BFG), liquid steel unit consumption of continuous casting, continuous casting slab unit consumption of hot rolling and hot metal ratio of steelmaking. Consequently, many efficient measures for reducing CO2 emissions have been proposed, such as removing CO2 contained in BFG, decreasing the hot metal ratio of Basic Oxygen Furnace (BOF), recycling BFG, optimizing the products’ structure, etc.

As new generation of low alloy high strength steel, WELDOX960 is extensively applied into heavy-duty fields including engineering machine etc. This paper adopts mixed gas protection welding to make multi-layer and multi-channel welding to low alloy high strength steel WELDOX960, using match methods with different intensities to prepare six groups of samples, respectively. The performances including joint tension and impact etc are tested for analysis after welding. The result shows that backing welding is the most important technique process in multi-layer and multi-channel welding, which has significant impact to joint performance, in the precondition that the strength is satisfied, if the material with lower strength is taken as backing layer, toughness and plasticity of the joint can be improved significantly. For example, tensile strength of sample 50-90 reaches 966.3Mpa, which is the same as 90-90, however, its toughness increases by 15%.

MIG welding overlaid austenitic stainless steel on low alloy Q345B. The overlay cladding comprises a transition layer and corrosion resistant layer. Overlaying specimens of transition layer with different thicknesses were prepared. The mechanical properties of joints were tested by micro-hardness, bending test and other methods. The results showed that the mechanical properties of specimen with ER309L welding wire as transition layer did not have splitting phenomena after being bended. There were no cracks. However, the specimen without transition layer had small crack or tiny cracks. When the transition layer thickness is changed, the performance of overlay cladding is essentially unchanged. The organizations of overlay cladding in four groups of specimens are similar, which are composed of austenite and ferrite, and ferrite was mostly distributed in strips and blocks.