Cold steel window handle cross wedge rolling process

 

    [Abstract] analyzed the cross wedge rolling conditions, with cold rolled steel window handle wedge example discusses plan selection process and process parameters determined. Access to basic trial rolling success. As used in the actual production need to be further improved precision.

 

    Keywords: cold cross wedge rolling process

 

1 Introduction

 

    Cold wedge rolling is a highly precise forming process, energy and materials significantly, especially in the processing of variable cross-section shaft has great application prospects. But its complex forming conditions, factors and more difficult to control. Roll surface design, processing more difficult. Therefore, wedge against the cold rolling process should be multi-dimensional depth research, it would be widely used in actual production. In recent years, we Xianfeng Machine Tool Plant in strong support of the azelaic 400mm cross wedge rolling mill rolling process carried out on experimental research, and steel window handle and other parts were relatively successful trial rolling.

 

    Figure 1 is a schematic steel window handle. Steel window handle for the mass production of the shaft parts, they are used for turning bars or rods, dimensional accuracy requirements are not too high, but requires surface finishing: with cold wedge rolling processing of such metal parts can be significant savings, improve productivity, and thus achieve lower production costs. Rolling process to determine the parameters.

 

    A smooth rolling, the workpiece must be continuously rotated, the rotation of the conditions to meet. To ensure the rotation, the following formula should be an extension forming wedge angle Lu Lu and Ar analogy a right angle Lu impact can extend tabulated one. L from the above formula or table visible, change the coefficient of friction of rotating conditions affecting p, followed by the mouth Ningbo, again Ar. A steel steel, copper-steel coefficient of friction 0.10 ~ 0.15, the J9 = 0.5-1.5. Or so. So take Lu = 0.5. , 1.0. Change the port, Ar test to verify the altercation made when appropriate, in general forming conditions, Lu take in a corner. Within the workpiece is to ensure continuous rotation during rolling.

 

In addition, to ensure quality within the workpiece after rolling, rolling process within the workpiece should be no cracks, hollow, that is full of Mannesmann effect does not occur. Therefore, the test piece shall be taken after rolling seized open it. Investigation to identify cracking rolling process conditions in order to avoid the actual rolling

 

3 selection process scheme

 

    In order to balance the axial rolling force, preferably a rolled steel window handle of the two. This allows productivity doubled. Adopt a process of rolling two, there are two solutions:

 

    The first solution is the small end (j5 7.5) docking, shown in Figure 2. In strict accordance with Parts are combined at the cutting burrs that may arise, increasing 1 mm. This ensures that the rolling part size, the small end is riveted end, cut along here, even if the second option burrs nor shadow big butt cone workpiece combinations shown in Figure 3. 410 mm of the bar with the original blank, j5 12 ring riveted. However, according to the maximum diameter of the blank-original diameter ≠ 12, the need to roll the axial length of more than 44 mm, in the case of single-wedge rolling, using 1. Extension angle, even if 3606 is also rolling rolls turn less than the length of this, let alone install a cutter; if taken more parallel wedge rolling, then to mold making and alignment increases the difficulty. By this program rolling in and the right angle and inverted cone shaft shoulder near the corresponding mold, was the complex forming surfaces '2], mold manufacturing and repair have a higher requirement. In addition, the blank is slightly more than the original diameter of the machine specifications. mm thick diameter hole at using closed for expanding forming Finally roller cutter from the rolling surface of the intermediate cut into two. By this program rolling, axial expansion was close to 32 mm, to spread out the +12 mm diameter, rolling +7.5 mm segments forming wedge wedged in advance, which can be at 250. So complete roll forming roll surface, the rear section of the roll surface can still be arranged cutter. Vertical shaft shoulder and tapered shaft shoulder can naturally forming, with their corresponding molds do not have to be made at the complex forming surfaces. In order to fit this roll forming, on the part drawing made two minor changes: the first is the handle of the knife to change by a large cone segments taper 10. 410 mm cone and cylinder composed of two sections. The second is close to 412 mm thick diameter at the small cone angle of the cone angle and forming a-cause.

 

    Since the second mill in the test solution can be rolled, and the mold structure is relatively simple, so the use of this rolling test program. 4 trial rolling and its results analysis

 

Expand the roll surface groove diagram shown in Figure 4. I inserted wedge shape, pushing outward flow of metal, in order to achieve the purpose of expanding the forming wedge from the I side of the vertical intercept metal role in the design of the mold, should be based on expanding the amount of metal to be determined intercept forming wedge I wedged the amount in advance.

 

Test mode with chilled cast iron, aluminum, copper and mild steel roll bar for trial. Alignment parallel to the roll diameter of the calibration after reduction rolling, the rolling process the workpiece in normal continuous rotation, rolling shape and size substantially to achieve the requirements of Parts (see Figure 5), no internal cracks rolling or hollow, basically meet the design requirements. Such as improved accuracy after catching a high rolling, you can put into industrial production.

 

    Seen from the test roll, roll manufacture and installation of precision forming of the workpiece has a greater impact, and reduction △ r changes did not affect the rotation of the workpiece sensitive.

 

    Try rolling in the machining accuracy are the following questions:

 

    (1) surface finish is not high enough, not yet reached Ra3.2 ~ Ra6.3 requirements. This is mainly due to the roll roll surface machining comparatively rough, and chilled cast iron brittle and easy to crack, so pass incomplete and seriously affect the rolling precision.

 

    (2) forming the wedge rolling out the workpiece side, a small amount of metal turned upward, forming a local surface interlayer (Figure 5) or flake-like debris. Especially the expanded diameter of 412 mm sections, metal phenomenon is more obvious on the turn, it will affect the accuracy of rolling an important factor. This indicates that the partial pressure of the rolling force in the radial direction relative value of P & lack of alignment have to go through the mouth and other parameters forming angle gradually overcome.

 

    (3) take the expanded diameter of 412 mm thick molded in rolling diameter does not meet the design requirements, usually ≯ 11,6 mm or so. This indicates that the amount of metal is not enough to intercept. Figure 7, in the rolling, forming wedge I intercepting surface vertical side AB is axially fixed position, when the forming wedge I the E'F 'goes to EF, marked area of ​​the metal textured O'F'FO is pushed out, then the FB are the plastic deformation section, is pressed out of the metal part of the upward flow, to achieve the purpose of expanding; also part of the surface is generated from the BD axial flow. As for the metal to which the direction of flow, to see which direction the flow resistance may be. If axial flow meter, in accordance with the calendar expanding the amount of metal required to calculate the amount of AB surface of the wedge. Since the metal produces an axial flow, in order to ensure the required amount of metal to intercept, then AB surface but also to advance wedging. If the amount in advance to obtain too large, the metal closed hole filled with sharp increase in resistance after forming, ak0 'can squeeze a bad pass. Many factors affect the metal flow, AB face wedged in advance the amount can not be accurately determined. It remains to be further studied in order to find out the law.

 

4 Conclusion

 

    Try to avoid taking hot rolling process parameters are basically suitable. Rolled steel window handle basically meet the design requirements. Workpiece dimensions accuracy and surface finish need to be further improved to meet the requirements of industrial production. To this end, on the cold wedge rolling process needs to carry out in-depth research.