Polytetrafluoroethylene steel-liner straight pipe and die pressing technology thereof

Abstract

The invention discloses a polytetrafluoroethylene steel-liner straight pipe and a die pressing technology thereof, and belongs to the technical field of steel-liner straight pipes. The polytetrafluoroethylene steel-liner straight pipe comprises an upper cover plate, a lower cover plate, and a hollow circular tube shaped mandrel which is arranged between the upper cover plate and the lower cover plate, wherein the outer side of the mandrel is sleeved with a rubber sleeve, and short tetrafluorohydrazine pipes sleeve the outer side of the rubber sleeve; the outer sides of the tetrafluorohydrazineshort pipes are sleeved with die-pressing straight pipes; the tetrafluorohydrazine short pipes are provided with tetrafluorohydrazine rings between the upper cover plate and the lower cover plate; the die-pressing straight pipes are provided with sealing surface dies between the upper cover plate and the lower cover plate; and the sealing surface dies are correspondingly connected to the upper cover plate and the lower cover plate through fasteners. According to the polytetrafluoroethylene steel-liner straight pipe, automatization or semi-automatization is achieved, so that the working efficiency is greatly improved; the cost control is easily refined; the problems of agglomerating, bridging and hollowing can be avoided; the workload of fine processing is decreased; the powder loss is greatly decreased; the rubber sleeve is prevented from breaking; and the product forming rate is increased.

Description

technical field [0001] The invention relates to a steel-lined straight pipe and its molding process, in particular to a steel-lined polytetrafluoroethylene straight pipe and its molding process, belonging to the technical field of steel-lined straight pipes. Background technique [0002] At present, the general molding process in the prior art is to put a mandrel mold with a rubber sleeve inside, and after positioning the device, fill the gap between the rubber mold and the steel pipe with PTFE powder, and then the flange sealing surfaces on both sides After installing the sealing surface mold on the position, fill the PTFE powder into the sealing surface mold and the steel cavity respectively, and then pressurize by injecting water pressure into the rubber sleeve or putting it into the isostatic pressure equipment after the cover is assembled. post-forming. [0003] The above molding method is a relatively popular traditional molding process at present. Due to the inherent...

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Problems solved by technology

[0004] 1) Low work efficiency;

[0005] 2) The wall thickness of the lining is seriously uneven, and the powder used for the workpiece of the same specification will have a large deviation. On the one hand, it will increase the cost, on the other hand, it is not conducive to quality control, and also seriously affects the refined cost control;

[0006] 3) Because PTFE powder is easy to agglomerate, it is easy to form agglomeration and bridging phenomenon locally when filling the powder, and local hollowing and scrapping will occur after molding;

[0007] 4) The lining of the sealing surface is severely uneven, and the amount of turning during post-processing is large, and the loss of powder is serious;

[0008] 5) The compression ratio is relatively large, and the internal air volume is relatively large during molding pressurization, and the rubber sleeve is easily damaged during pressurization, which will cause water ingress in the PTFE layer, and the workpiece scrap rate is high

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