SU495176A1 - Method of multi-pass plasma-arc surface cutting - Google Patents

Description

one

The invention relates to methods for plasma-arc surface cutting and can be used for smelting defects in welds occurring at great depths, with a limited length of cut, as well as for cutting defects into castings.

The known method of multi-pass plasma arc cutting, in which the plasma arc is oriented at an angle of 30 ° to the surface of the workpiece.

In addition to sushi, a natural disadvantage of the known method is that with an increase in the depth of smelting, the productivity of processing sections of limited length sharply decreases.

According to the proposed method for increasing the productivity of the process, when processing sections of limited length, with each subsequent pass, the arc is set in a position symmetrical to the position of the previous pass relative to the axis perpendicular to the surface of the product being processed, with the jet tilted in the opposite direction, and during the second pass the arc is displaced from the edge first the grooves to the distance, the rabbi JZ of its width, and the angle of inclination of the arc increase with each odd pass by 5-10.

The proposed method allows to obtain grooves with the ratio h / b, which ensures an increase in the productivity of cutting operations, where / g is the depth of the melted groove and b is the width of the groove.

Pa FPG. 1 but the execution of the first pass is shown: in FIG. 2 - the second.

The proposed method is carried out as follows.

During the first pass, the plasmatron is set in position so that the plasma arc is directed relative to the surface of the workpiece at an angle a of 20-30 °. In this case, for a definite arc burning time, a groove is formed in the metal, which is limited by the front and side edges. The extreme depth of the groove is limited by the conditions for the formation of a vertical frontal cut.

Claims (1)

With such a cutting edge, the conditions for removing the metal from the cutting cavity become worse. The plasma arc cannot be recessed into the workpiece. The resulting groove has a width equal to b and a depth hi. During the cutting process, the position of the plasmatron remains unchanged, then the plasmatron is deployed symmetrically about an axis perpendicular to the surface of the product, does not change the angle of inclination, and is moved to a position equal to the distance from the edge of the groove (point A). In this case, the plasmatron is installed in this way. so that the arc is directed to point B, which is separated from point A by 3 times the length of the resulting groove (Vs & i). The depth of the groove has a value of / 12, which is 15-20% higher than the depth hi. When the plasmatron is displaced by an equal distance, they provide the most optimal profile of the groove with the formation of a gentle side edge along which the smelted metal in the third pass will be easily removed from the cut cavity, as a result of which the further process proceeds under the best conditions. Thus, when choosing a distance above the second pass, a jumper of unmelted metal is formed, and 15 the metal melted at the second pass fills the groove obtained at the first, resulting in a cut cavity consists of two separate grooves, which reduces the performance of subsequent passages - 20 need to remove non-molten metal jumpers between the grooves. At a distance of less than one side edge is not obtained flat, since the side edge overlaps with the frontal edge, 25 which worsens the condition of removing the molten metal during the third pass. After the second groove is made, the plasmatron is re-deployed and set so that the plasma arc axis is-30 aligned to the edge of the groove. In this case, the angle of inclination of the plasma arc with respect to the surface of the product being processed is increased by 5-10 ° compared to the angle during the first and second passes, and the deepening of the plasma arc is made from the edge of the groove obtained during the first pass. As a result, a groove is obtained, the depth of which increases to hz (l, 5 + 2) fti. Each even groove with this process scheme provides an inclined plane that facilitates removal of molten metal from the cut cavity with odd grooves (first, third, etc.), which provides a significant increase in depth over a multiple number of passes. The invention of the method of multi-pass plasma-arc surface cutting, in which the plasma arc is oriented at an angle of 30 ° to the surface of the workpiece, characterized in that, in order to increase the productivity of the process when processing sections of limited length, each subsequent arc is set to a position symmetrical the position of the previous passage from the axis 1, perpendicular to the treated surface of the product, with the jet tilted in the opposite direction, and during the second pass the arc with eschayut from the edge of the first groove by a distance equal to Va its width, and angle of arc at every odd passage is increased by 5-10 °.