电力铁塔用18 mm厚160角钢Q420C(/%:≤0.20C,1.00~1.70Mn,≤0.55Si,≤0.035S,≤0.035P,0.02~0.20V,≥0.015Als)的冶金流程为80 t BOF-LF-CC-车制工艺。利用光学显微镜、SEM以及能谱分析仪对热轧角钢角部裂纹进行了分析,结果表明,裂纹周...电力铁塔用18 mm厚160角钢Q420C(/%:≤0.20C,1.00~1.70Mn,≤0.55Si,≤0.035S,≤0.035P,0.02~0.20V,≥0.015Als)的冶金流程为80 t BOF-LF-CC-车制工艺。利用光学显微镜、SEM以及能谱分析仪对热轧角钢角部裂纹进行了分析,结果表明,裂纹周围存在脱碳层及铁素体膜,裂纹处发现S富集及在晶界析出的AlN破坏了钢基体的连续性;得出连铸振痕谷底的夹渣、成分偏析,热应力和弯曲矫直应力导致了角钢沿晶界开裂。通过降低[N]至0.008 0%,控制Als 0.017%~0.022%,Mn/S≥80,钢水过热度≥25℃,保护渣牯度0.73 Pa·s,矫直温度≥950℃等工艺措施,使连铸坯的优质品率由原25.78%提高至85%,有效地降低了角钢角部裂纹的发生。展开更多
试验用Q420C钢(/%:0.18C,0.34Si,1.40Mn,0.013P,0.011S,0.066V,0.018Als,0.011 0N)铸坯的冶炼工艺为80 t BOF-LF-CC。采用Gleeble-1500D热模拟试验机测试Q420C钢连铸坯的600~1400℃热塑性,并利用金相显微镜、扫描电镜以及透射电子显微...试验用Q420C钢(/%:0.18C,0.34Si,1.40Mn,0.013P,0.011S,0.066V,0.018Als,0.011 0N)铸坯的冶炼工艺为80 t BOF-LF-CC。采用Gleeble-1500D热模拟试验机测试Q420C钢连铸坯的600~1400℃热塑性,并利用金相显微镜、扫描电镜以及透射电子显微镜分析断口形貌及金相组织和研究凝固偏析和析出物粒子对铸坯热塑性的影响。结果表明,Q420C钢第Ⅰ脆性区为>1250~1350℃;第Ⅲ脆性区为700~1050℃;在1050~1250℃,断面收缩率大于60%。工业试验结果表明,通过控制Als含量0.015%~0.020%,适当降低二冷比水量(足辊段7~8t/h,Ⅰ段5.5~6.5 t/h,托辊段14±1t/h),铸坯矫直温度≥1050℃,轧材开裂率由原45.3%降至4.6%。展开更多
Background： Many studies have suggested that cigarette smoking and polymorphisms of resi stin and glutathione peroxidase-1 （GPx-1） genes are closely correlated with tile pathogenesis of nonalcoholic lhtty liver dis...Background： Many studies have suggested that cigarette smoking and polymorphisms of resi stin and glutathione peroxidase-1 （GPx-1） genes are closely correlated with tile pathogenesis of nonalcoholic lhtty liver disease （NAFLD）. However, few reports have investigated these associations with respect to NAFLD susceptibility. We, therefore, exalnined the distribution of polymorphisms in GPx-l and resistin genes in NAFLD patients and healthy controls and analyzed the relationship between these polymorphisms and smoking status. Methods： Nine hundred NAFLD patients and 900 healthy controls were selected, and the genetic polymorphisms of resistin gene promoter- 420C/G and GPx- 1 gene Pro 198Leu were analyzed by polymorphism-polymerase chain reaction （PCR） in DNA extracted from peripheral blood leukocytes. Interactions between tile two mutants and the gene-environment interaction with cigarette smoking were also analyzed. Results： Genotype frequencies of 420C/G （GG） and Pro198Leu （LL） were significantly higher in NAFLD cases （49.56% and 50.11%, respectively） compared with healthy controls （23.67% and 24.22%, respectively） （P = 0.0069： P= 0.0072）. Moreover, the risk of NAFLD with 420C/G （GGJ was significantly higher than in controls （odds ratio [OR] =3.1685, 95% confidence interval （（7） 1.9366-5.2073）. Individuals carrying Pro198Leu （LL） had a high risk of NAFLD （OR - 3.1424, 95% C/= 1.7951 5.2367）. Combined analysis of the polymorphisms showed that the -420C/G （GG）/Pro198Leu （LL） genotype was significantly more common in the NAFLD group than in the control group （39.44% vs. 12.78%, respectively, P 0.0054）, while individuals with -420C/G （GG）/Pro198Leu （LL） had a high risk of NAFLD （OR = 5.（1357, 95% CI= 3.1852 7.8106）. Moreover, the cigarette smoking rate in the NAFLD group was significantly higher than in tile control group （OR = 1.8990, P = 0.0083 in the smoking index （SI） _〈400 subgroup： OR = 5.0937, P = 0.0051 in the SI 〉400 subgroup）, and statistical analysis suggested a positive interaction between cigarette smoking and 420C/G （GG） （y = 5.6018 in tile SI≤400 subgroup; γ - 4.4770 in the SI 〉400 subgroup） and Pro198Leu （LL） （y = 5.7715 in the SI ≤400 subgroup： γ 4.5985 in the SI 〉400 subgroup） in increasing the risk of NAFLD. Conclusion： NAFLD risk factors include -420C/G （GG）, Pro198Leu （LL） and cigarette smoking, and these three factors have a significant additive effect on NAFLD risk.展开更多
文摘试验用Q420C钢(/%:0.18C,0.34Si,1.40Mn,0.013P,0.011S,0.066V,0.018Als,0.011 0N)铸坯的冶炼工艺为80 t BOF-LF-CC。采用Gleeble-1500D热模拟试验机测试Q420C钢连铸坯的600~1400℃热塑性,并利用金相显微镜、扫描电镜以及透射电子显微镜分析断口形貌及金相组织和研究凝固偏析和析出物粒子对铸坯热塑性的影响。结果表明,Q420C钢第Ⅰ脆性区为>1250~1350℃;第Ⅲ脆性区为700~1050℃;在1050~1250℃,断面收缩率大于60%。工业试验结果表明,通过控制Als含量0.015%~0.020%,适当降低二冷比水量(足辊段7~8t/h,Ⅰ段5.5~6.5 t/h,托辊段14±1t/h),铸坯矫直温度≥1050℃,轧材开裂率由原45.3%降至4.6%。
文摘Background： Many studies have suggested that cigarette smoking and polymorphisms of resi stin and glutathione peroxidase-1 （GPx-1） genes are closely correlated with tile pathogenesis of nonalcoholic lhtty liver disease （NAFLD）. However, few reports have investigated these associations with respect to NAFLD susceptibility. We, therefore, exalnined the distribution of polymorphisms in GPx-l and resistin genes in NAFLD patients and healthy controls and analyzed the relationship between these polymorphisms and smoking status. Methods： Nine hundred NAFLD patients and 900 healthy controls were selected, and the genetic polymorphisms of resistin gene promoter- 420C/G and GPx- 1 gene Pro 198Leu were analyzed by polymorphism-polymerase chain reaction （PCR） in DNA extracted from peripheral blood leukocytes. Interactions between tile two mutants and the gene-environment interaction with cigarette smoking were also analyzed. Results： Genotype frequencies of 420C/G （GG） and Pro198Leu （LL） were significantly higher in NAFLD cases （49.56% and 50.11%, respectively） compared with healthy controls （23.67% and 24.22%, respectively） （P = 0.0069： P= 0.0072）. Moreover, the risk of NAFLD with 420C/G （GGJ was significantly higher than in controls （odds ratio [OR] =3.1685, 95% confidence interval （（7） 1.9366-5.2073）. Individuals carrying Pro198Leu （LL） had a high risk of NAFLD （OR - 3.1424, 95% C/= 1.7951 5.2367）. Combined analysis of the polymorphisms showed that the -420C/G （GG）/Pro198Leu （LL） genotype was significantly more common in the NAFLD group than in the control group （39.44% vs. 12.78%, respectively, P 0.0054）, while individuals with -420C/G （GG）/Pro198Leu （LL） had a high risk of NAFLD （OR = 5.（1357, 95% CI= 3.1852 7.8106）. Moreover, the cigarette smoking rate in the NAFLD group was significantly higher than in tile control group （OR = 1.8990, P = 0.0083 in the smoking index （SI） _〈400 subgroup： OR = 5.0937, P = 0.0051 in the SI 〉400 subgroup）, and statistical analysis suggested a positive interaction between cigarette smoking and 420C/G （GG） （y = 5.6018 in tile SI≤400 subgroup; γ - 4.4770 in the SI 〉400 subgroup） and Pro198Leu （LL） （y = 5.7715 in the SI ≤400 subgroup： γ 4.5985 in the SI 〉400 subgroup） in increasing the risk of NAFLD. Conclusion： NAFLD risk factors include -420C/G （GG）, Pro198Leu （LL） and cigarette smoking, and these three factors have a significant additive effect on NAFLD risk.
