Abstract: An ultra-heavy steel plate with low cracking sensitivity and low yield ratio, the mass percentages of chemical components of the steel plate are C 0.05-0.09; Si 0.2-0.4; Mn 1.3-1.6; Al 0.02-0.04; Nb 0.03-0.08; V 0.03-0.08; Cr 0.1-0.5; Ni 0.1-0.5; Mo 0.1-0.3; Cu 0.2-0.5; Ti 0.01-0.02; P?0.015; S?0.003; N?0.007, the balance being Fe and inevitable impurities; the carbon equivalent is ?0.43, the cold cracking sensitivity coefficient Pcm is ?0.20. A low cracking sensitivity and low yield ratio steel plate with a thickness of 40-70 mm is manufactured by the process steps of KR molten iron pretreatment-converter smelting-LF refining-RH vacuum degassing-continuous casting-lid-covering slow cooling for the continuous casting slabs-casting slabs heating-controlled rolling-controlled cooling-hot straightening-air cooling and so on.

Abstract: An ultra-heavy steel plate with low cracking sensitivity and low yield ratio, the mass percentages of chemical components of the steel plate are C 0.05-0.09; Si 0.2-0.4; Mn 1.3-1.6; Al 0.02-0.04; Nb 0.03-0.08; V 0.03-0.08; Cr 0.1-0.5; Ni 0.1-0.5; Mo 0.1-0.3; Cu 0.2-0.5; Ti 0.01-0.02; P?0.015; S?0.003; N?0.007, the balance being Fe and inevitable impurities; the carbon equivalent is ?0.43, the cold cracking sensitivity coefficient Pcm is ?0.20. A low cracking sensitivity and low yield ratio steel plate with a thickness of 40-70 mm is manufactured by the process steps of KR molten iron pretreatment-converter smelting-LF refining-RH vacuum degassing-continuous casting-lid-covering slow cooling for the continuous casting slabs-casting slabs heating-controlled rolling-controlled cooling-hot straightening-air cooling and so on.

Abstract: An outdoor unit of an air-conditioner and two-pipe and three-pipe air-conditioning systems having the same are provided. The outdoor unit includes a compressor defining an outlet and an inlet; a first four-way valve defining a first valve communicated with the outlet, second and third ports communicated with the inlet; a second four-way valve defining second and third ports communicated with the inlet; an outdoor heat exchanger defining a first refrigerant valve Communicated with the fourth port of the first four-way valve; a first gas pipe defining a first end connected with the second and third ports of the first and second four-way valves and, the inlet; a second gas pipe defining a first end connected with the fourth port of the second four-way valve; a third gas pipe defining a first end connected with the outlet and a second end connected with the first port of the second four-way valve.

Abstract: An outdoor unit of an air-conditioner and two-pipe and three-pipe air-conditioning systems having the same are provided. The outdoor unit includes a compressor defining an outlet and an inlet; a first four-way valve defining a first valve communicated with the outlet, second and third ports communicated with the inlet; a second four-way valve defining second and third ports communicated with the inlet; an outdoor heat exchanger defining a first refrigerant valve Communicated with the fourth port of the first four-way valve; a first gas pipe defining a first end connected with the second and third ports of the first and second four-way valves and, the inlet; a second gas pipe defining a first end connected with the fourth port of the second four-way valve; a third gas pipe defining a first end connected with the outlet and a second end connected with the first port of the second four-way valve.