The microstructure of 40Cr and T10A steel sample and its surface to be welded is ultra-fined through salt-bath cyclic quenching and high frequency hardening, then the surface is cleaned. Under non-vacuum and no shield...The microstructure of 40Cr and T10A steel sample and its surface to be welded is ultra-fined through salt-bath cyclic quenching and high frequency hardening, then the surface is cleaned. Under non-vacuum and no shielded gas, the welding parameter of isothermal superplastic solidphase welding and the effect of surface microstructure prior to pressure welding on the quality of joint are studied. At the temperature of 730~750℃ and at initial strain rate of (2~4) × 10-4 s-l, the strength of the joint is up to or close to that of 40Cr base metal in 3-5 min pressure welding展开更多
In this paper, uising the thermo-decomposition quantitative method to determine the alite content in cement clinker has been studied. It is shown that the alite content determined by the thermo-decomposition method is...In this paper, uising the thermo-decomposition quantitative method to determine the alite content in cement clinker has been studied. It is shown that the alite content determined by the thermo-decomposition method is very close to that obtained by the optical microscopy method. The practical quantitative analysis of alite in cement clinker was carried out by the thermo-decomposition method and a quite satisfactory result has been obtained.展开更多
The effects of CaSO4 additive and burning temperature on the formation and properties of high-alkali clinker as well as their optimal control range were studied by means of chemical analysis, physical examination , XR...The effects of CaSO4 additive and burning temperature on the formation and properties of high-alkali clinker as well as their optimal control range were studied by means of chemical analysis, physical examination , XRD, DTA and EPMA. The results show that a proper addition of CaSO4 may convert alkalis to R2S04, reduce melt viscosity, considerably improve the forming environment of alite. during burning. hence the setting and hardening of clinker develop normally. If CaSO4 were too much , however , that excess SO3 with Al2O3 would dissolve into C2S to hinder C3S forming and produce K2SO4 ·CaSO4 ·H2O during hydratlon , to lead to quick setting of the paste. The optimal CaSO4 content expressed as SO3/R2O mole ratio in clinker is 0. 6-1. 0, A high temperature can decrease the riscosity and increase the rate of forming C3S nuclei , so not only helping overcome the harm of alkali but al,so supplementing imperfection of sulpfiate. It is better to burn a high alkali clinker with CaSO4 addition abore 1400℃.展开更多
基金supported by the Henan Natural Science Foundation of China under Grant No.984040900.
文摘The microstructure of 40Cr and T10A steel sample and its surface to be welded is ultra-fined through salt-bath cyclic quenching and high frequency hardening, then the surface is cleaned. Under non-vacuum and no shielded gas, the welding parameter of isothermal superplastic solidphase welding and the effect of surface microstructure prior to pressure welding on the quality of joint are studied. At the temperature of 730~750℃ and at initial strain rate of (2~4) × 10-4 s-l, the strength of the joint is up to or close to that of 40Cr base metal in 3-5 min pressure welding
文摘In this paper, uising the thermo-decomposition quantitative method to determine the alite content in cement clinker has been studied. It is shown that the alite content determined by the thermo-decomposition method is very close to that obtained by the optical microscopy method. The practical quantitative analysis of alite in cement clinker was carried out by the thermo-decomposition method and a quite satisfactory result has been obtained.
文摘The effects of CaSO4 additive and burning temperature on the formation and properties of high-alkali clinker as well as their optimal control range were studied by means of chemical analysis, physical examination , XRD, DTA and EPMA. The results show that a proper addition of CaSO4 may convert alkalis to R2S04, reduce melt viscosity, considerably improve the forming environment of alite. during burning. hence the setting and hardening of clinker develop normally. If CaSO4 were too much , however , that excess SO3 with Al2O3 would dissolve into C2S to hinder C3S forming and produce K2SO4 ·CaSO4 ·H2O during hydratlon , to lead to quick setting of the paste. The optimal CaSO4 content expressed as SO3/R2O mole ratio in clinker is 0. 6-1. 0, A high temperature can decrease the riscosity and increase the rate of forming C3S nuclei , so not only helping overcome the harm of alkali but al,so supplementing imperfection of sulpfiate. It is better to burn a high alkali clinker with CaSO4 addition abore 1400℃.
