CN108581381B - Method for transforming box girder of large-arm oil cylinder base of door gripper - Google Patents

Abstract

The invention relates to heavy engineering hoisting equipment of a gantry steel grabbing machine. A method for improving a box girder of a base of a door-grab large-arm oil cylinder comprises the steps of firstly measuring and recording the distance between two triangular brackets, then supporting the two triangular brackets by two seamless steel pipes, cutting an upper plate, a lower plate, a front plate and a rear plate of the box girder, selecting a cutting point at the position which is 100 cm away from the left end and the right end of 1/4 of the box girder, measuring and recording the distance between the two triangular brackets again, and spot-welding the upper plate, the lower plate, the front plate and the rear plate at the left end and the right end of a box girder part to finish assembly; and arranging tarpaulin on the two triangular frames to enclose and block, preheating, welding, preserving heat and cooling. The invention effectively solves the hidden trouble of the equipment and realizes the safe and stable operation of the equipment.

Description

Method for transforming box girder of large-arm oil cylinder base of door gripper

Technical Field

The invention relates to heavy engineering hoisting equipment of a gantry steel grabbing machine.

Background

The Shanxi Tai steel stainless steel limited company has 2 imported door type steel grabs, mainly undertake the supply of the steel mill smelting raw materials, it is a A grade apparatus of company's key management and control, because long-time continuous use, cause the key position structure fatigue of car body, mainly reflect the frequent crack of the base box body part of the large arm cylinder, through adopting multiple methods, process several times, the time of each use is shorter and shorter, can't be dealt with completely, the apparatus downtime is not short to increase, bring very big influence to the operation of guaranteeing production and safety, and import spare part need order, the cycle is one year, the amount of money is up to 200 ten thousand, consider the exploration to the transformation method of the whole box beam from every aspect compelling.

Disclosure of Invention

The invention aims to solve the technical problems that: how to reform transform a door type steel grabbing machine box girder.

The technical scheme adopted by the invention is as follows: a method for modifying a box girder of a base of a large-arm oil cylinder of a door gripper comprises the following steps of installation

Firstly, paving double-layer asbestos cloth at the lower part of a box girder, measuring and recording the distance between two triangular frames, then supporting the two triangular frames by adopting two seamless steel pipes, and welding the two seamless steel pipes at the inner sides of the two triangular frames side by side;

step two, cutting the box girder upper plate, the box girder lower plate, the front plate and the rear plate, wherein the box girder of the oil cylinder base with the door grabbing large arm is fixed at two ends, the maximum bending moment is positioned at the middle point and two end points of the girder, the bending moment from 1/4 positions of the two ends is zero, and the crack is positioned in the position 1/4 position away from the two ends, so that the cutting points are selected at the positions 30 cm away from the two ends 1/4, the cutting points of the box girder upper plate and the box girder lower plate are closer to the two ends of the box girder base with the door grabbing large arm than the cutting points of the box girder front plate and the box girder rear plate, and the distance between the cutting points of the box girder upper plate and the box girder lower plate and the cutting points of the;

step three, measuring and recording the distance between the two triangular frames again, observing whether the two triangular frames deform, if so, correcting, hanging the prepared box girder part which is completely the same as the cut part at the cut position, detecting and adjusting the alignment of the upper plate, the lower plate, the front plate and the rear plate respectively, and performing spot welding on the upper plate, the lower plate, the front plate and the rear plate at the left end and the right end of the box girder part to finish the assembly;

step four, arranging tarpaulin barriers on the two triangular frames, preheating the peripheries of welding seams before welding, wherein the preheating temperature is 150 ℃, continuously welding after welding to keep the temperature of the welding seam not lower than 100 ℃, firstly welding the front plate and the rear plate, simultaneously welding four seams of the front plate and the rear plate by four welders in a welding process, taking the progress into consideration, keeping synchronization, welding the upper plate and the lower plate after the welding of the front plate and the rear plate is finished, simultaneously welding the left welding seam and the right welding seam of the upper plate by the two welders, and simultaneously welding the left welding seam and the right welding seam of the lower plate;

and step five, immediately heating the welding seam after welding, keeping the heating temperature at 350 ℃ for 1 hour, and then wrapping with asbestos cloth for heat preservation and cooling.

The invention has the beneficial effects that: after the method is applied to the overall transformation and replacement of the box girder, the problem of structural fatigue cracking is effectively solved, and the tracking is adopted, so that the performance is reliable and stable, and the expected target is realized. The welding shutdown is 160 hours every year, which is calculated from the aspect of equipment shutdown, and the time can be correspondingly saved after the transformation, so that the production guarantee supply can be fully realized. From the view point of operation safety, after the new method is applied and modified, the hidden danger of the equipment is effectively solved, and the safe and stable operation of the equipment is realized. From the aspect of expense, the cost is calculated, and with the success of applying the new domestic method for modification, about 200 thousands of spare parts cost, about 100 thousands of tools and labor cost are effectively saved, and about 300 thousands of total effect is created.

Drawings

FIG. 1 is a schematic structural view of the present invention;

the steel plate comprises a front plate 1, a front plate 2, an upper plate 3, a first tripod 4, a seamless steel pipe 5, a second tripod 6, a box girder 7, a rear plate 8 and a lower plate.

Detailed Description

As shown in figure 1, the modification method effectively solves the problem of frequent cracking of the large-arm oil cylinder base box body, realizes the perfect replacement of domestic structures and imported structures, and is specifically implemented as follows:

laying double-layer asbestos cloth protection on the lower portion of the box girder, measuring and recording the distance between two triangular frames before dismantling the box girder, then supporting the triangular frames, and manufacturing 2 seamless steel pipe supports with the length of 1600mm, the pipe diameter of 108mm and the wall thickness of 4.5 mm; and welding the support rods in place and fixing the support rods in the inner side of the tripod side by side.

Cutting cracks of an upper plate, a lower plate, a front plate and a rear plate of a box girder, fixing two ends of a large-arm oil cylinder seat girder, positioning the maximum bending moment at the middle point and two end points of the girder, and positioning the bending moment at 1/4 away from the two ends to be zero, so that a port is preferably selected near the point, a bevel cutting method is selected, 900mm is cut on the upper plate and the lower plate of the box girder, 700mm is cut on the front plate and the rear plate of the box girder, V grooves are adopted on the cuts, fine grinding duty measurement is required to be finely finished, and the gap between the grooves is

To the smallest possible.

After the dismantling is finished, measuring and recording the distance between the two triangular frames for the second time, observing whether deformation exists, keeping the support, hoisting the replaced box girder component in place, matching with a chain block to carry out assembly on a new box girder, fixing the front plate, the rear plate, the upper plate and the lower plate of the replaced box girder component with the front plate, the rear plate, the upper plate and the lower plate of the bridge in a flush manner by using a measuring tool, wherein the error is +0.05mm, and carrying out spot welding on the periphery of the box girder to finish the assembly;

preheating before welding and maintaining the temperature, arranging a tarpaulin enclosure around the tarpaulin enclosure, and taking windproof measures to ensure level 1; secondly, a heating fire ring is made of a 1-inch steel pipe in advance, the periphery of the welding seam is preheated by propane gas before welding, the preheating temperature is 150 ℃, and continuous welding is carried out after welding so as to keep the temperature of the welding seam part not lower than 100 ℃.

Welding sequence, firstly, four welders weld four vertical seams of a web plate (a front plate and a rear plate) at the same time, the progress is considered mutually, and the basic synchronization is kept; after the vertical seam is finished, two welders weld the flat seam and the overhead seam of the upper plate and the lower plate, each welder is responsible for the flat seam and the overhead seam at one position, and the flat seam and the overhead seam are welded alternately so as to keep the interlayer temperature from being reduced and the upper part and the lower part of the interlayer from being deformed in a balanced manner.

And (3) after welding, removing hydrogen, immediately heating the welding line by using a propane heating ring after welding is finished, keeping the heating temperature at 350 ℃ for 1 hour, and then wrapping by using asbestos cloth, preserving the heat and cooling.

The welding method and the welding material are as follows: gas shield welding is adopted, mixed gas protection is adopted, and ER50-6 is selected as a welding wire.

Claims (1)

1. The utility model provides a door claw large arm hydro-cylinder base case roof beam transformation method which characterized in that: the method comprises the following steps:

firstly, paving double-layer asbestos cloth at the lower part of a box girder, measuring and recording the distance between two triangular frames, then supporting the two triangular frames by adopting two seamless steel pipes, and welding the two seamless steel pipes at the inner sides of the two triangular frames side by side;

step two, cutting the box girder upper plate, the box girder lower plate, the front plate and the rear plate, wherein the box girder of the oil cylinder base with the door grabbing large arm is fixed at two ends, the maximum bending moment is positioned at the middle point and two end points of the box girder, the bending moment from 1/4 positions of the two ends is zero, and the crack is positioned in the position 1/4 positions away from the two ends, so that the cutting points are selected at the positions 30 cm from the left and right of the 1/4 positions of the two ends, the cutting points of the box girder upper plate and the box girder lower plate are closer to the two ends of the box girder of the oil cylinder base with the door grabbing large arm than the cutting points of the box girder front plate and the box girder rear plate, and the distance between the cutting points of the box girder upper plate and;

step three, measuring and recording the distance between the two triangular frames again, observing whether the two triangular frames deform, if so, correcting, hanging the prepared box girder part which is completely the same as the cut part at the cut position, detecting and adjusting the alignment of the upper plate, the lower plate, the front plate and the rear plate respectively, and performing spot welding on the upper plate, the lower plate, the front plate and the rear plate at the left end and the right end of the box girder part to finish the assembly;

step four, arranging tarpaulin barriers on the two triangular frames, preheating the peripheries of welding seams before welding, wherein the preheating temperature is 150 ℃, continuously welding after welding is started to keep the temperature of the welding seam part not lower than 100 ℃, firstly welding the front plate and the rear plate, simultaneously welding four seams of the front plate and the rear plate by four welders, taking the progress into consideration, keeping synchronization, welding the upper plate and the lower plate after the welding of the front plate and the rear plate is finished, simultaneously welding the left welding seam and the right welding seam of the upper plate by the two welders, and simultaneously welding the left welding seam and the right welding seam of the lower plate;

and step five, immediately heating the welding seam after welding, keeping the heating temperature at 350 ℃ for 1 hour, and then wrapping with asbestos cloth for heat preservation and cooling.

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