1.1 Basic

Casting is the basis of mechanical manufacturing process technology, for various reasons in the production process there will be a variety of defects, especially in the automotive industry in the diesel engine, gasoline engine cylinder block, such a complex thin-walled parts rejection rate is higher. In addition, a variety of machinery and equipment in the cast iron pieces are easily damaged during use. So far, the international and domestic have yet to solve the above problems of the theory and methods.

1.2 International News

Internationally, as the cast iron cold welding (welding refers to the former do not have to warm up) and still spend 1940's extension of the United States invented the nickel-iron electrode mainly pure, under certain conditions, can be nickel-based powder spray, near U.S. production of 308 Welding Wires Manufacturers (with a resemblance to the present invention). Compared with the present invention fusion zone HB ≤ 300 (the invention of ≤ 240), and, when not in use continuous welding (due to slag and prone to crack).

1.3 Domestic News

The 1980s, the State Planning Commission to Beijing 211 Factory Chen Zhongsheng (Professor of Engineering) of "low carbon steel electrode," in "Seven. Five", "Seven. Eight" during the promotion, proved that the technology can not effectively welding cast iron to solve the fundamental problem; to the nineties, Chongqing University of the spray, recommended by the Sichuan Provincial Planning Commission focus, diesel engine manufacturers in certain applications, but in the application process the following problems:

â‘  welding temperature is easily controlled. The technology used before welding gas welding flame heating to be welded at the heating temperature is by artificial visual, low temperature solder is not strong, the temperature is too high would be too hard at welding;

â‘¡ welding preparation work is more cumbersome, technically demanding to be welded at the clean up before welding;

â‘¢ welding process have special requirements for the operation, improper operation could easily lead to the loss of liquid solder;

â‘£ The welding surface area and thickness are higher, and is only suitable for welding large area and shallow face;

⑤ welding staff working conditions, when temperatures are high in summer, warm in winter operation a long time the workpiece.

In summary, although the availability of certain external spray conditions, to achieve mechanical processing and thermal cracking, but the technology exists because many of the above shortcomings and drawbacks, and in practice works in cast iron is still hot crack weldment (The determination of thermal cracks more than 80% probability), so that in large scale applications is limited.

1.4 patents and technology from theory to solve several problems:

(1) white issue, no heat treatment after welding.

The current domestic and international welding of cast iron were white solve the problem, now the United States invented the wire 308 (currently the most advanced) In the ideal case the thickness of the fusion zone of up to 0.1MM, chilling tendency evident. The present invention uses a special cold Stainless Steel Welding Wires and semi-automatic CO2 protection technology. Current density, a large cooling rate after welding, base metal and welding fusion zone microstructure of hardened layer from the white layer analysis is intermittent, generally <0.07MM, before processing tool for cutting little effect, for after welding is not need to heat treatment.

(2) are not resolved before welding heat, do not crack the problem.

Welding cast iron is for local rapid heating, the temperature differential is inevitable, when the thermal stress is greater than the tensile strength of the welded pieces of cast iron is bound to hot cracking. Wire in the design of the present invention the use of the chemical composition of the lowest yield limit "200MPA, and up to 400-500MPA, so that once the process of welding stress and deformation over 200MPA when the weld and to decrease stress, and thus the most effective to prevent thermal cracks appear.

(3) to solve the fusion problem

Some cast iron, due to "graphite" thick, high temperature or oil in the environment, in the welding process to a certain extent affect the fusion of a serious roll when not welding. Welding technology in the present invention facilitate the process of graphite combustion, combustion of CO can promote the fusion of the weld pool boiling greatly changed.

Before and after the welding wire is not in the heat treatment may destroy the original machining accuracy, the fusion zone Hbmax ∠ 240, welded joints and base metal such as intensity, color, consistent with the parent material for all kinds of complicated welding thin-walled parts . Can be used in ductile iron, gray iron castings and other types of welding cast iron products.

Since the invention of cast iron technology solve the fundamental problem of welding, which produces a corresponding increase in labor rates and substantial savings in energy.

94 years since the technology in Jiangsu, "JAC Power" Large enterprises have been successfully applied, diesel engine repair business for the past few years has reached 10 million units, economic losses of several thousand million, and achieved good economic benefits, the enterprise has been praise and recognition.

CO2 produced by the patented cast iron wire is now dedicated to market.