CN113500157B

CN113500157B - Manufacturing method of double lifting hooks for large-scale metallurgy crane

Info

Publication number: CN113500157B
Application number: CN202110787054.7A
Authority: CN
Inventors: 庄明亮; 魏明
Original assignee: Wugang Group Xiangyang Heavy Equipment Material Co ltd
Current assignee: Wugang Group Xiangyang Heavy Equipment Material Co ltd
Priority date: 2021-07-13
Filing date: 2021-07-13
Publication date: 2023-04-25
Anticipated expiration: 2041-07-13
Also published as: CN113500157A

Abstract

The invention relates to a manufacturing method of a double lifting hook of a large-scale metallurgical travelling crane, which comprises the following steps: 1) Heating the steel ingot, namely heating the steel ingot to 100-150 ℃ below the solidus temperature of the material, and preserving heat for a certain time to ensure that the core and the surface temperature are consistent and completely austenitized; 2) Forging a double-hook plate, wherein the forging step comprises the steps of steel ingot axial upsetting, radial stretching, material distribution, round bar drawing, drain pan upsetting, slab end stretching, drawing and trimming for each section; 3) Heat treatment of double hook plates; 4) Machining and forming; the invention improves the utilization rate of materials, reduces the manufacturing cost of the lifting hook, ensures the core quality of the lifting hook, and improves the product percent of pass and the safety of the lifting hook.

Description

Manufacturing method of double lifting hooks for large-scale metallurgy crane

Technical Field

The invention relates to the field of metallurgical tools, in particular to a manufacturing method of a double lifting hook of a large-scale metallurgical travelling crane.

Background

The lifting hook of the metallurgical crane is an important part of the metallurgical crane, and the safety performance requirement is high when the crane is operated to often lift molten metal. The lifting hook has two kinds of double lifting hooks and single lifting hook, because the double lifting hook is more even than single lifting hook atress, and the security performance is good, so large-scale (more than 100 tons) metallurgical crane lifting hook generally adopts double lifting hook. The double-hook material is generally of 20Mn steel grade, 35CrMo steel grade and the like, and 35CrMo steel grade is more used.

The lifting hook belongs to a safety piece, the internal quality requirement is higher, the flaw detection is required during manufacturing, and the flaw detection level is generally not lower than GB/T6402-2008 III, so that the requirement can be met only by forging. The forging forming is mainly divided into die forging and free forging, and because the large double-lifting hooks have a large specification and are generally single-piece and small-batch, if the die forging is adopted, the tonnage of the hydraulic press is required to be large, and meanwhile, a special die is required to be used, so that the manufacturing cost is extremely high, and the large double-lifting hooks generally adopt a free forging process.

The process route for manufacturing the large double-lifting hook by most domestic manufacturers is as follows: heating steel ingot, forging into a plate blank, normalizing and tempering, flame cutting and machining and forming. Because the hook structure is special, hook head part width is more than 5 times of hook pole part, and the slab finally cuts out through flame at hook pole part end most, and in addition hook head department processing, metal cutting volume is big, causes the utilization ratio of steel ingot extremely low, only about 20%, manufacturing cost is higher, simultaneously, flame cutting still can change the metallographic structure of material, influences the mechanical properties of material, is unfavorable for the security of lifting hook.

Disclosure of Invention

The invention aims to solve the problems of the existing metallurgical lifting hook manufacturing method, and provides a manufacturing method of a double lifting hook for a large-scale metallurgical crane, which improves the utilization rate of materials, reduces the manufacturing cost of the lifting hook, ensures the core quality of the lifting hook, and improves the product percent of pass and the safety of the lifting hook.

The specific scheme of the invention is as follows, a manufacturing method of a double lifting hook of a large-scale metallurgy crane comprises the following steps:

1) Heating the steel ingot, namely heating the steel ingot to 100-150 ℃ below the solidus temperature of the material, and preserving heat for a certain time to ensure that the core and the surface temperature are consistent and completely austenitized;

2) Forging a double-hook plate, wherein the forging step comprises the steps of steel ingot axial upsetting, radial stretching, material distribution, round bar drawing, drain pan upsetting, slab end stretching, drawing and trimming for each section;

3) Heat treatment of double hook plates;

4) And (5) machining and forming.

Further, in the step 2), the first fire is firstly upset to 50% -60% of the original ingot height along the axial direction of the steel ingot, then is widened to the width W and the thickness H along the radial direction, the length L is pressed down from the riser end of the blank, and a round rod with a certain diameter is pulled out, wherein the diameter of the round rod is larger than that of the hook rod.

Furthermore, the L/W is more than or equal to 0.4, and the width-to-thickness ratio W/H is controlled between 2.5 and 3.5.

Further, in the step 2), after the first forging, the blank is returned to the furnace for heat preservation, then the second forging is performed, and the strip clamp is axially upsetted to 45% -55% of the length of the original hook section blank by adopting a punching drain pan, so that the width of the hook section blank is wider than the width of the double hook plate, the width of the hook section blank is prolonged to the width of the double hook plate, and the round blank of the hook rod section is prolonged to the round bar size of the double hook plate.

Further, in the step 2), the end part of the slab of the hook head section is lightly pressed by adopting a punching leakage disc after the second forging, the transition part of the hook head section and the round slab of the hook rod section is trimmed, the round slab of the hook rod section is drawn to the required size of the double hook plate, the concentricity of the double hook plate is immediately checked after the forging, and if the central line deviation of the slab and the round rod is corrected by adopting an offset anvil method.

The invention has the following beneficial effects:

1. the pressing length of the hook rod section/the blank width of the hook head section is more than or equal to 0.4, so that the metal in the center of the hook head section is greatly deformed, the center quality of the hook can be ensured, and the product percent of pass is improved;

2. the hook rod section does not need to cut a large amount of metal materials by flame, the material utilization rate is improved by more than 25%, and the manufacturing cost of the hook can be reduced;

3. the lifting hook is not cut by flame in the later stage of manufacturing, and mechanical processing is adopted, so that the safety risk of the lifting hook caused by material tissue change due to flame cutting can be reduced, and the safety performance of the double lifting hooks is ensured.

Drawings

FIG. 1 is a schematic diagram of a double hook structure of a large metallurgical crane of the present invention;

FIG. 2 is a side view of FIG. 1;

FIG. 3 is a front view of a double hanger plate forging blank of the present invention;

FIG. 4 is a side view of FIG. 3;

in the figure: 1-hook rod and 2-hook head.

Detailed Description

Referring to fig. 1-4, the embodiment is 160t crane double-hook, the material is 35CrMo, the forging blank of the double-hook plate is as shown in fig. 3, wherein: w=1550mm, l1=880mm, l2=1320mm, d=Φ310mm, h=310 mm, and the specific manufacturing process is as follows:

1) The temperature is kept for 1-2h by using a 5.4t octagonal ingot with the diameter of 715mm and the ingot height of 1660mm and a red-cast steel ingot at 850 ℃ and is raised to 1240 ℃ at the speed of less than or equal to 100 ℃/h for 3h.

2) Taking out the steel ingot, upsetting the steel ingot to 800mm along the axial direction of the steel ingot by adopting an upsetting plate, radially widening the steel ingot to 1300 multiplied by 400mm, separating and discharging the steel ingot from a riser part to obtain an effective length of 210mm, drawing the steel ingot to D=phi 500mm, and returning the steel ingot to the furnace for heat preservation at 1240 ℃ for 2h.

3) Taking out the blank in the step 2), and upsetting to 600mm by adopting an upsetting plate and a punching leakage disc belt clamp. And drawing the big end (slab end) to 1550 multiplied by 310mm, repeatedly trimming the shape and the size of the big end (slab end) by putting a punching drain pan, and drawing the small end (round slab end) to phi 310mm after the shape and the size are qualified.

4) Air cooling the formed double-hook plate blank to 300-350 ℃ on the surface, feeding the blank into a furnace, preserving heat for 2 hours at 600 ℃, heating to 900 ℃ at less than or equal to 100 ℃/h, preserving heat for 6 hours, discharging and rapidly cooling (air cooling) to 400 ℃ on the surface, feeding the blank into the furnace, preserving heat for 2 hours at 500 ℃, heating to 650 ℃ at less than or equal to 100 ℃/h, preserving heat for 12 hours, and discharging.

5) And processing the forging blank after heat treatment by adopting a processing center until the size of the lifting hook is reached.

Claims

1. A manufacturing method of a double lifting hook of a large-scale metallurgical travelling crane is characterized by comprising the following steps: the method comprises the following steps:

3) Heat treatment of double hook plates;

4) Machining and forming;

the first fire in the step 2) is firstly upsetting to 50% -60% of the original ingot height along the axial direction of the steel ingot, then widening to the width W and the thickness H along the radial direction, pressing down the length L from the riser end of the blank, and drawing a round rod with a certain diameter, wherein the diameter of the round rod is larger than that of the hook rod; the L/W is more than or equal to 0.4, and the width-thickness ratio W/H is controlled between 2.5 and 3.5;

and 2) returning the blank to the furnace for heat preservation after the first fire forging in the step 2), and then performing the second fire forging, upsetting the blank with pliers along the axial direction by adopting a punching drain pan to 45% -55% of the length of the original hook section slab, so that the width of the hook section slab is wider than the width of the double hook plate, and the width of the hook section slab is pulled to the width of the double hook plate, and the round blank of the hook rod section is pulled to the round bar size of the double hook plate.