Introduction of forging fine cutting technology of caterpillar chain rail of construction machinery


The cutting quantity of punch edge is large, because the cutting edge and the contact time of fine cutting position are long and the cutting life of hot forging is low, so the cutting life is relatively long. The production efficiency is guaranteed. The die is split type, and the cutting die and punch can be changed quickly by combining the cutting edge insert block with the matrix.

The mouth demands more rigor on the cutting edge and punch edge. During the fine cutting, the contact time of the chain rail forgings is longer than that of the general cutting edge and forgings, the amount of cutting is larger, and the hardness is higher at the temperature, which requires the cutting edge to be high. L-6 electrode we choose ST, which has better high temperature hardness than STL-21 phase. At the same time, in the precision cutting station, the precision cutting edge is sprayed with water for cooling every half hour after production. The forgings produced by fine cutting process are shown in Figure 4.

According to the empirical formula, thickness)×σ(tensile strength)=1.2×(680+165+170)mm×4mm×15kg/mm2=73.08t the plugging load of the general cutting and fine cutting station is as follows: the plugging load of the general cutting station is P1=1.2×L(plugging circumference)×t(flying edge on the drawing;

When the rail section die forging cavity is supposed to be non-fine cutting chain, the forgings mismove and positioning and other reasons to form "black skin" phenomenon in order to prevent the two sides of the chain rail section and the nut face in the subsequent processing by, there is a margin of 0.5 ~ 1mm generally we are on the two sides and the nut face, generally take 7° and the Angle of the mold.

Caterpillar track section forgings for precision cutting, punching trimming when eager to product size because the two sides and nut in the forging and the convex mold cavity is not different, and is used when punching trimming and finish forging, milling two-sided positioning jig are much more precise positioning accuracy is machining, cutting removal at the same time in order to cut, mold cavity to adopt allowance imagine us caterpillar track section of forgings, There is no allowance for the parent surface, that is, two sides and screw, the size of the figure is the same as the size of the product, and the degree is 5° from the mold. To consider at the same time when cutting, burr pull out of the die is easy, base on the reduction of 0.3mm so the size of the die on this basis.

In recent years, the cutting process began to rise chain rail forging fine, two sides and nut surface fine cut to the size of the forging when the chain rail, and mechanical processing is no longer carried out, the surface of the two machining procedures to cut milling double-sided and push nuts, production efficiency thus improved, production cost reduction. Previously, CF and other companies have adopted this process to produce on a large scale (Figure 1). Foreign companies such as CAT, ITM, BERCO and D. Rail forging products on the mass production of my company has also completed in a variety of chains, to other products are gradually promoted. The chain rail joint forgings of pitch as an example in this paper, a 190mm process is introduced to the forging fine cutting.

Requirements are increasingly harsh on the wrong movement of forging. Process comparison and conservative, the die forging cavity is used to eliminate the margin of the assumption that the fine cutting process is used to produce the chain rail section. If the forgings are wrong when the displacement is large, the "flash black skin" will form the fine cutting forgings, and the removal amount will become larger than the current die side, and the thorn is pulled out to form the hair. The allowance of wrong shift is smaller, so fine cutting forgings. For the chain rail with m pitch, the quantity requirement of 190m is ≤ 0.7mm, which is incorrectly moved in the general cutting process, and the quantity requirement of ≤ 0.3mm is incorrectly moved in the fine cutting process.

Cutting precision in order to improve the precision, precision cutting edge life as much as possible at the same time, the use of two stations for punching cutting, forging flanging and even skin that is a station general cutting, suitable allowance and leave, the allowance will be removed two stations fine cutting, the processing surface to obtain products. The positioning of the forgings on the punch at the same time in order to ensure that when finishing cutting, the skin is cut off the pin hole and the connection of the sleeve hole at the finishing cutting position.

According to the calculation results, 5T ×80?? Therefore, the equipment can meet the requirements of fine cutting process production P1+ P2= 173.02T < 252t(31, can work at the same time and two stations.

With the fine cutting process after the chain rail section forgings, the allowance to reduce the material quota can be through the die forging cavity, analysis of the manipulation rate to improve the material, and push the nut surface two processing processes at the same time to eliminate the subsequent milling double-side, but also shorten the manufacturing cycle of the product in reducing the processing cost at the same time. To promote the economic benefits of enterprises and the promotion and use of the forging and cutting technology of chain rail joints made by the market.

Section product market demand 190mm pitch chain rail, in more than 300,000 pieces of my company's annual output. Hot die forging press for forging the forgings using 2500T, force machine for punching edge cutting 315T crank pressure, forging final forging punching edge cutting production process is: pre. Secondary forging dimensions are shown in Figure 2.

The quality of the cutting surface has a great influence on the clearance pair between the punch and the concave die. It is easy to adjust the clearance of the concave and convex die on the general cutting surface by 1.0mm. According to 0.5mm manufacturing precision cutting surface concave and convex die clearance, cutting surface quality to ensure, burr reduction.