CN111098098B

CN111098098B - High-pressure internal core-pulling forming method for bent pin joint

Info

Publication number: CN111098098B
Application number: CN202010005537.2A
Authority: CN
Inventors: 田开宜
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-01-03
Filing date: 2020-01-03
Publication date: 2021-07-20
Anticipated expiration: 2040-01-03
Also published as: CN111098098A

Abstract

The invention relates to a high-pressure internal core-pulling forming method of a curved pin joint, which comprises the following steps of: preparing materials: preparing a stainless steel pipe; and (3) internal core-pulling molding: the stainless steel pipe is sequentially subjected to core pulling molding in three different molds, and the core pulling molding method comprises the following steps: carrying out internal expansion and external necking, and carrying out high-pressure internal core-pulling internal expansion and external necking molding on two ends of the stainless steel pipe; and a step B: rolling the middle part of the reducer pipe subjected to the step A to obtain the reducer pipe with the designed size of the tubular step connecting joint in the middle part of the reducer pipe; and a step C: performing high-pressure internal core-pulling sizing, flattening and eccentric guiding on the reducer pipes with different diameters at two ends after the step B to obtain a curved pin joint rough blank; step D: and C, performing thread rolling, machining and ultrasonic internal and external mirror surface treatment on the rough blank of the curved pin joint after the step C to obtain a finished curved pin joint, and finishing a plurality of steps by a high-pressure internal core-pulling process at one time to ensure that the excircle size of two ends of the curved pin joint, the level of a flat surface of the middle section of the curved pin joint and the circular arc of the circular arc surface are full.

Description

High-pressure internal core-pulling forming method for bent pin joint

Technical Field

The invention relates to a method for manufacturing an eccentric reducing pipe, in particular to a high-pressure internal core-pulling forming method of a curved pin joint.

Background

At present, bathroom products are increasing day by day, and the foot that curves is as tap's main accessory, and its quality problems direct influence tap whole life-span, and the foot that curves plays the effect between connecting tube and the tap, and the foot that curves bears a whole set of tap weight under the condition of normal installation, through long-time expend with heat and contract with cold, with alkaline material contact and material oxidation, causes the life-span of the foot that curves to shorten to influence whole tap's life-span. In order to improve the strength and corrosion resistance of the curved foot, in the prior art (the first generation technology), a casting process is adopted to manufacture the stainless steel curved foot, and the casting process of the stainless steel curved foot is as follows: the method comprises the steps of profiling manufacturing, wax mold pressing, wax mold assembling, paint dipping, sanding, hardening and drying (repeated for multiple times), dewaxing, molding, roasting, burning, sand shakeout, cleaning, and is limited to the defects of the process, the defects of surface pockmarks, black spots, sink marks, pits, oxide sand inclusion, island-shaped bulges and the like appear on the finished product of the bent foot, the appearance of the product is influenced, and the performance and the yield of the product are reduced, because the molecular structure of the cast finished product is not compact, the structure is loose, and the material contains more impurities, local rust or rust spots are easy to appear on the surface, the processing process of the bent foot casting method is difficult, the hardness of the cast and molded bent foot is relatively high, the cutter is seriously worn, the price is relatively high, and the second-generation technology, namely the extrusion molding method is adopted to manufacture the bent foot on the market, as patent numbers: CN103028911B discloses a method for extrusion molding of a bent leg joint, which is applied on day 12/11 in 2012 and published on day 22/04 in 2015, comprising the steps of (1): preparing a stainless steel pipe; step (2): annealing the stainless steel pipe in the step (1); and (3): and (2) sequentially extruding the annealed stainless steel pipe in a plurality of different dies, wherein the extrusion process comprises the following steps: a. Necking, wherein one end of the stainless steel pipe is subjected to necking to obtain a reducer pipe; b. Flattening, namely flattening the middle part of the reducer pipe into a designed size; c. Reaming, namely reaming two ends of the flattened reducer pipe to obtain the reducer pipe with tubular connectors of designed sizes at two ends; D. pressing eccentricity, namely pressing eccentricity of the reducer pipe with the tubular connector; obtaining a curved-foot rough blank; and (4): the method is characterized in that the bent foot rough blank is subjected to thread rolling, machining and polishing respectively to obtain a bent foot finished product, but the technology still has a plurality of defects, the bent foot rough blank is produced by a multi-die multi-step extrusion method, the phenomena of high defective rate and high rejection rate are caused in the production process, the sizes of circumscribed circles at two ends of a bent foot joint are inaccurate, the straightness is poor, the straightness at two ends cannot be guaranteed in the extrusion step B and the flattening step, and the bent foot joint is easy to raise fox, and the middle section and the straight line close parts at two ends of the bent foot joint form an arc in the eccentric pressing step D, so that the thread tooth tips are not full, and the torsion cannot be guaranteed.

Disclosure of Invention

The technical problem to be solved by the present invention is to solve the above-mentioned deficiencies of the prior art,

provides a high-pressure internal core-pulling forming method of a curved pin joint.

In order to achieve the purpose, the invention provides the following technical scheme: a high-pressure internal core-pulling forming method of a curved pin joint is characterized by comprising the following steps:

preparing materials: preparing a stainless steel pipe;

and (3) internal core-pulling molding: the stainless steel pipe is sequentially subjected to core pulling molding in three different molds, and the core pulling molding method comprises the following steps: carrying out internal expansion and external necking, and carrying out high-pressure internal core-pulling internal expansion and external necking molding on two ends of the stainless steel pipe;

and a step B: rolling the middle part of the reducer pipe subjected to the working procedure A to obtain the reducer pipe with a tubular step connecting joint with a designed size in the middle part;

and a step C: performing high-pressure internal core-pulling sizing, flattening and eccentric guiding on the reducer pipes with different diameters at two ends after the step B to obtain a curved pin joint rough blank;

step D: and C, performing thread rolling, machining and ultrasonic internal and external mirror surface treatment on the rough blank of the curved-foot joint after the step C to obtain a finished curved-foot joint.

By adopting the technical scheme, the inner core-pulling forming process B rolls the middle part of the reducer pipe with different diameters at two ends to obtain the reducer pipe with the design-size tubular adjusting connecting joint in the middle part, so that the straightness of two ends of the middle section of the reducer pipe is ensured in the subsequent process C for flattening and eccentric guiding, and arcing is avoided, thereby ensuring that thread tips at two ends of a bent foot joint are full when thread rolling is carried out in the process D, avoiding the problem that thread torsion cannot be ensured because the thread tips are not full when thread rolling is carried out subsequently due to the fact that the middle section of the bent foot joint forms an arc with the straight-line approaching parts at two ends when eccentric pressing is carried out in the middle of the bent foot joint by adopting a multi-die multi-step extrusion method in the second generation technology, namely the extrusion forming method, completing a plurality of processes once by high-pressure inner core-pulling of the process C, ensuring the size and the straightness of two ends of the bent foot joint, and ensuring the level of the flat surface of the middle section of the bent foot joint and the arc fullness of the arc surface, thereby obtain the pleasing to the eye perfect curved foot and connect, caused curved foot in the production process of second generation technique and connect the sunken bellied problem of middle part fold, and because in the process C high pressure internal loose core once only accomplish a plurality of processes to the manpower and manufacturing cost have been saved in a large number, have avoided causing in the production process of second generation technique that defective percentage, disability rate remain high problem.

The invention has the beneficial effects that: the high-pressure internal core pulling process is adopted to complete a plurality of processes at one time, so that the size and the straightness of the outer circles of the two ends of the bent pin joint, the level of the flat surface of the middle section of the bent pin joint and the full arc of the arc surface are ensured, the problem that wrinkles in the middle of the bent pin joint are sunken and raised in an extrusion forming method is avoided, the high-pressure internal core pulling process is used for completing a plurality of processes at one time, manpower and production cost are greatly saved, and the problems that defective rate and rejection rate are high in the production process of the extrusion forming method are avoided.

The present invention will be described in further detail with reference to the accompanying drawings and examples.

Drawings

Fig. 1 is a schematic structural view of a stainless steel pipe according to an embodiment of the present invention.

Fig. 2 is a schematic structural view of a stainless steel tube after internal expansion and external contraction according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a stainless steel tube after rolling according to an embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a stainless steel tube after high-pressure internal loose core sizing, flattening and eccentric guiding according to an embodiment of the invention.

Fig. 5 is a schematic structural diagram of a stainless steel pipe subjected to thread rolling, machining, and ultrasonic internal and external mirror surface treatment according to an embodiment of the present invention.

Detailed Description

Referring to fig. 1-5: a high-pressure internal core-pulling forming method of a curved pin joint is characterized by comprising the following steps:

preparing materials: preparing a stainless steel tube as shown in FIG. 1;

and (3) internal core-pulling molding: the stainless steel pipe is sequentially subjected to core pulling molding in three different molds, and the core pulling molding method comprises the following steps: performing internal expanding and external necking, and performing high-pressure internal core pulling and internal expanding and external necking molding on two ends of the stainless steel pipe, as shown in figure 2;

and a step B: rolling the middle part of the reducer pipe subjected to the step A to obtain the reducer pipe with the tubular step connecting joint with the designed size in the middle part, as shown in FIG. 3;

and a step C: performing high-pressure internal core-pulling sizing, flattening and eccentric guiding on the reducer pipes with different diameters at two ends after the step B to obtain a curved pin joint rough blank, as shown in FIG. 4;

step D: and C, performing thread rolling, machining and ultrasonic internal and external mirror surface treatment on the rough blank of the curved-foot joint subjected to the step C to obtain a finished curved-foot joint product, wherein the finished curved-foot joint product is shown in figure 5.

Claims

1. A high-pressure internal core-pulling forming method of a curved pin joint is characterized by comprising the following steps:

preparing materials: preparing a stainless steel pipe;