Study on Cracking Tendency and Mechanism of Gray Cast Iron Laser Cladding

In this paper, NiCrSiB and CoWC35 powder has been used in laser cladding of gray cast iron. The cracking tendency has also been discussed. The cracks have been observed with a scan electron microscopy to analyze the cracking mechanism. The results show that cracks have not appeared in NiCrSiB cladding. Nevertheless, the cracking tendency of CoWC35 cladding is extremely high and there are both cold cracks and hot cracks in the cladding. The cracking tendency of laser cladding depends on physical properties of the cladding material and plasticity and roughness of the cladding.

茶园套种薄壳山核桃不同坡位土壤养分调查分析

采集松阳县山地茶园套种薄壳山核桃山场位于海拔在120-300米间向阳坡面上不同坡位土壤样品,分析土壤基本理化特性及有效铁、有效锰、有效铜、有效锌等微量营养元素的变化情况,结果表明:随着坡位升高,土壤有效铁、有效锰、有效铜含量呈现出下降趋势,而有效锌含量呈现升高趋势。在实际操作中,应采取必要的措施防止水土流失,合理控制土壤的酸性,增施磷、钾肥。