CN102943201A - Production method of low-strength cold forging steel not requiring heat treatment - Google Patents
Production method of low-strength cold forging steel not requiring heat treatment Download PDFInfo
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- CN102943201A CN102943201A CN201210514384XA CN201210514384A CN102943201A CN 102943201 A CN102943201 A CN 102943201A CN 201210514384X A CN201210514384X A CN 201210514384XA CN 201210514384 A CN201210514384 A CN 201210514384A CN 102943201 A CN102943201 A CN 102943201A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 64
- 239000010959 steel Substances 0.000 title claims abstract description 64
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 27
- 238000010438 heat treatment Methods 0.000 title claims abstract description 13
- 238000010273 cold forging Methods 0.000 title abstract 7
- 238000001816 cooling Methods 0.000 claims abstract description 31
- 238000005096 rolling process Methods 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 claims abstract description 16
- 229910052799 carbon Inorganic materials 0.000 claims description 17
- 238000007669 thermal treatment Methods 0.000 claims description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 8
- 239000000126 substance Substances 0.000 claims description 3
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052748 manganese Inorganic materials 0.000 claims description 2
- 239000011572 manganese Substances 0.000 claims description 2
- 229920001296 polysiloxane Polymers 0.000 claims description 2
- 238000007670 refining Methods 0.000 abstract description 2
- 239000002994 raw material Substances 0.000 description 9
- 238000012360 testing method Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 238000005265 energy consumption Methods 0.000 description 5
- 238000000137 annealing Methods 0.000 description 4
- 230000008901 benefit Effects 0.000 description 4
- 238000005457 optimization Methods 0.000 description 4
- 238000005275 alloying Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229910000859 α-Fe Inorganic materials 0.000 description 3
- 238000005336 cracking Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 238000003801 milling Methods 0.000 description 2
- 235000019362 perlite Nutrition 0.000 description 2
- 239000010451 perlite Substances 0.000 description 2
- 238000004080 punching Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910000954 Medium-carbon steel Inorganic materials 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 229910000754 Wrought iron Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
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Abstract
The invention relates to a production method of low-strength cold forging steel not requiring heat treatment, which comprises the following steps: 1, heating a blank: heating the blank to 1100-1200 DEG C in a heating furnace prior to rolling; 2, performing multi-pass roll forming on a bar mill to obtain a product having a required specification and size; 3, according to the requirements of the cold forging steel product for different strength levels, selecting different initial rolling temperatures and finishing temperatures, and controlling the finishing temperature to be about 750-850 DEG C; 4, after the rolled product is finished, immediately cooling for 1-10 seconds, and ensuring that the temperature of the rolled product is 550-700 DEG C after final cooling; and 5, after the rolled product is cooled, performing air cooling on a roller way for 5-15 seconds, then transferring onto a cooling bed, and cooling to room temperature. According to the invention, the cold forging steel produced from the components by the rolling-controlled and cooling-controlled process has excellent cold forging property; and meanwhile, due to grain refining, the cold forging steel product has high strength, and the mechanical properties can completely meet the corresponding requirements for the performance of the cold forging steel product in national standards.
Description
Technical field: the present invention relates to a kind of production method of steel, especially a kind of production method of exempting from the low strong cold heading rivet spiral shell steel of thermal treatment belongs to materials science field.
Background technology: in machinofacture departments such as modern automobile, tractors, extensively adopt the higher standardized component of cold heading technique production interchangeability and other parts, such as screw, bolt, nut, pin, rivet etc., this raw material for cold-heading often is called " riveting spiral shell steel ".Riveting spiral shell steel is mainly used in fastener products, fastening piece is as widely used mechanical basic part, have industry characteristic various in style, the huge market demand, be widely used in the national economy every field such as machinery, electric, automobile, communications and transportation, aerospace.
Riveting spiral shell steel cold heading cracking problem in the cold-heading process is perplexing manufacturer always.Chemical composition and component segregation, wire rod original quality, Spheroidizing Annealing tissue produce conclusive impact to riveting spiral shell steel cold heading cracking.Therefore, manufacture urgently increases high-ductility, high-mouldability and demand with riveting spiral shell steel of some strength.
According to national standard, tensile strength reaches other riveting spiral shell steel of 490MPa level and need adopt the ML30Mn raw material after heat treatment to obtain, and tensile strength need adopt ML40, ML40Mn and ML45, ML45Mn raw material after heat treatment to obtain near other riveting spiral shell steel of 600MPa level.The ML15 steel can only be the 373MPa rank and will obtain by thermal treatment for the production of tensile strength.Adopt the prior heat treatment method to produce ML15, ML30Mn, ML40, ML40Mn, ML45 and ML45Mn steel, cost is high, energy consumption is large, and its mechanical performance index is low.Riveting spiral shell steel is delivered goods with As rolled for the manufacture of fastener products such as bolts the time.Owing to must guarantee certain intensity rank, such as 5.8 grades of low strength bolts, often guaranteeing by improving carbon content.According to standard GB/T/T3098.1-2010 " fastening piece mechanical property bolt, screw and double-screw bolt " requirement, the carbon content of 5.8 grades of low strength bolts reaches as high as 0.55%, and manufacturer often adopts 35 steel to be used for the production of 5.8 grades of low strength bolts.And higher carbon content has caused raw material hardness when cold-heading higher, and plasticity is not enough, causes follow-up cold heading technique to stablize and carries out.For this reason, raw material often needs the annealed material transformation of the way of carrying out before cold-heading, and mechanical property just can meet the demands.Because the raw material cold heading performance is poor, instrument consumption is very large when cold-heading, energy consumption is high.Simultaneously, various heat treating faults in heat treatment process, also usually occur, guarantee that quality product is very difficult.Develop without the directly riveting spiral shell steel of cold upset forming of annealing, can save alloy, simplify working process, reduce energy consumption, raise labour productivity.
As everyone knows, low-carbon (LC) riveting spiral shell smelting steel is relatively easy, and carbon content is lower, and rolling performance is better when becoming a useful person.If can adopt controlled rolling and control method of cooling production riveting spiral shell steel, to in below the ML35, low-carbon (LC) riveting spiral shell steel realizes flexible rolling, with carbon in low-carbon (LC) generation, seek out and a kind ofly namely can reduce production costs, can significantly improve again the production method of steel comprehensive mechanical property, to situ production important practical significance will be arranged.
Summary of the invention: purpose of the present invention is exactly to solve the problem that exists in the low strong cold heading rivet spiral shell steel production, design a kind of soft steel that does not contain alloying element, by adopting Controlled Rolling And Controlled Cooling, a kind of hot rolled rod of direct production, without the direct cold upset forming of annealing, cold heading performance is very good, also no longer pass through normalizing thermal treatment thereafter, the product indices that cold-heading goes out can satisfy standard GB/T/T 6478-86 " cold heading steel technical qualification " to the requirements of riveting spiral shell steel comprehensively, greatly reduce production cost, improved labour productivity.
For achieving the above object, the technical solution used in the present invention is: exempt from the production method of the low strong cold heading rivet spiral shell steel of thermal treatment, the steps include:
1, blank heating.Rollingly front blank is heated to 1100~1200 ℃ in process furnace.
2, be shaped through multi-pass rolling at merchant bar mill, obtain the product of desired specification.The road number of times is determined by factors such as billet size, final dimension, milling train patterns.
3, according to the varying strength rank requirement of riveting spiral shell product made from steel, select different open rollings, finishing temperature, the control finishing temperature is about 750~850 ℃.
4, after the rolled piece finish to gauge immediately through 1~10 second cooling, guarantee that eventually cold rear rolled piece temperature is between 550~700 ℃.Cooling water flow, pressure can require to determine with different specifications according to the varying strength rank.
5, after the rolled piece cooling on roller-way through 5~15 seconds air cooling, then arrive cold bed, until room temperature.
Described blank chemical component is: between the carbon content 0.10~0.20%; Silicone content is between 0.05~0.10%; Manganese content is between 0.05~1.00%; In addition, p and s content should lack as far as possible, and general control is below 0.04%, in order to improve the cold heading performance of bar.
The cold heading steel that adopts mentioned component and cooling controlling and rolling controlling process to obtain, become in the process of riveting spiral shell product made from steel in cold-heading, taking full advantage of cold heading steel increases because low-carbon (LC) makes the ferrite content in its metallographic structure, effectively improved its cold deformation performance, therefore plasticity is very high in process of production for riveting spiral shell steel, and cold heading performance is very good.Owing to grain refining, riveting spiral shell product made from steel has higher intensity simultaneously, and mechanical property satisfies national standard fully to the corresponding requirements of riveting spiral shell product made from steel performance.
The advantage of maximum of the present invention is: by Composition Design and controlled rolling and controlled cooling, produce the low strong cold heading rivet spiral shell steel of hot rolling, this steel is rolling when rear, need not anneal, the direct cold upset forming of bar, cold heading performance is very good, the riveting spiral shell product made from steel that cold-heading becomes also no longer need pass through normalizing thermal treatment, just can obtain tensile strength surpasses 400MPa, unit elongation>20% above 500MPa, yield strength mechanical property, and strong cold heading rivet spiral shell steel is hanged down in the exempt from thermal treatment of yield tensile ratio between 0.7~0.8, production cost is reduced, and quality product improves, and has improved economic benefit.
Description of drawings:
Fig. 1 is the schema of producing screw with low strong cold heading rivet spiral shell steel of the present invention.
Embodiment:
Embodiment: carried out field conduct for the manufacture of fastener products-5.8 grade low strength bolt as example take riveting spiral shell steel.Adopt the ML15 steel to produce riveting spiral shell steel raw material through controlled rolling and controlled cooling, go out 5.8 grades of low strength bolt products (the general common employing ML35 steel of this product is cold upsetting production after heat treatment) of M6 * 65 without the direct cold-heading of thermal treatment.
Behind certain factory's merchant bar mill, installed a cover control refrigerating unit additional.This production line has 18 horizontally and vertically alternative milling trains, wherein roughing, in roll and finishing train each 6.Producing the used material of cold heading steel is the ML15 steel, and the blank specification is the square billet of 150mm, and the final dimension of cold heading steel is Φ 7.0mm.Enter the control refrigerating unit after rod iron is rolling and cool off, the Total Water of whole refrigerating unit is 300m
3/ h, hydraulic pressure are 1.4MPa.
The tapping temperature of blank is 1100 ℃, rolling through 18 passages after, the temperature out of finished frame is 960-1040 ℃, enter subsequently the control cold.Rolled piece velocity of discharge 10.0m/s, water cooler length 8m, the surface temperature of cold heading steel is 600~700 ℃ after the control cooling, rate of cooling is greater than 80 ℃/s.Then be chilled to room temperature by roller-way in the cold bed sky.Be HB217 to the cold heading steel product test hardness that obtains.
As shown in Figure 1: above-mentioned cold heading steel through mechanical turning processing, is obtained the bar (among Fig. 1 topmost shown in) of Φ 5.65 * 250mm.Bar raw material is without annealing, directly carry out the header bolt test at the Z47-6 multistage cold former, obtain the thick bar material (upper several the 2nd bars among Fig. 1) of Φ 5.75 through just punching, then essence punching and undergauge obtain Φ 5.84 untrained work in-process (upper several the 3rd bars among Fig. 1), produce the GB5782 hex hd finished product bolt of M6 * 65 after cut edge (upper several the 4th bars among Fig. 1), the thread rolling (upper several the 5th bars among Fig. 1).
During this bar cold-heading, the cold deformation performance is very good, compares with traditional medium carbon steel material, and forming property is good, and scrap rate is very low.5.8 grades of low strength bolts of the M6 that cold-heading goes out * 65 guarantee load, wedge load test by the standardized component industry standard on 30 tons of universal testing machines, in test-results such as table 1, the table 2.
Table 1 guarantees loading test
Table 2 wedge load test
By in table 1 and 2 as seen, become bolt through the ML15 steel raw material cold-heading of controlled rolling and controlled cooling after, mechanical property satisfies standard GB/T/T3098.1-2010 " fastening piece mechanical property bolt, screw and double-screw bolt " fully to the corresponding requirements of 5.8 grades of low strength bolts.
The present invention has following features:
1, material composition optimization
Contain C<0.2%, do not contain alloying element and make riveting spiral shell steel cost.
2, rolling Technology Optimization
1. low-carbon (LC) riveting spiral shell steel speed of cooling (15~40 ℃/s) in the scope, speed of cooling is faster, ferrite crystal grain is thinner, mechanical property is better.In 700~550 ℃ of temperature ranges of final cooling temperature, final cooling temperature is lower behind the controlled rolling and controlled cooling, and perlite sheet spacing is thinner, and intensity and plasticity are better.
2. do not control cold hot rolling test after the low temperature rolling of control cold-peace after, the low temperature rolling cold through control behind the pair rolling of low-carbon (LC) riveting spiral shell steel, tissue improves, and its mechanical property all is better than the riveting spiral shell steel of pair rolling.
3. for low-carbon (LC) riveting spiral shell steel, cause the quick cooling of more perlite and thinner ferrite crystal grain, more more crucial than finishing temperature.Rolling sample under higher finishing temperature condition has good mechanical property because cooling off fast.In production, more be easy to realize in the quick cooling of comparatively high temps finish to gauge.
3, Product Process optimization
Low strong riveting spiral shell steel through controlled rolling and controlled cooling does not need its tensile strength of thermal treatment to surpass 500MPa, yield strength surpasses 400MPa, unit elongation surpasses 20%, yield tensile ratio is between 0.7~0.8, every mechanical performance index has not only all surpassed ML30Mn and the ML35Mn steel of produced in conventional processes, and has reached even surpassed the standard-required of ML40 and ML45 steel.Exempted the heat treatment step of product, made product processes obtain optimization.
4, reduce cost and energy consumption
The riveting spiral shell product made from steel of controlled rolling and controlled cooling does not contain alloying element in actual production, reduced simultaneously production process, has reduced cost and energy consumption, has improved economic benefit, and market application foreground is wide.
5, the present invention is not only to energy-saving and emission-reduction, and owing to having reached purpose with low-carbon (LC) carbon in generation by controlled rolling and controlled cooling, realizes that for China low-carbon economy has Great significance.
Claims (1)
1. exempt from the production method of the low strong cold heading rivet spiral shell steel of thermal treatment, the steps include:
(1) blank heating: rollingly front blank is heated to 1100~1200 ℃ in process furnace;
(2) blank is shaped through multi-pass rolling at merchant bar mill, obtains the product of desired specification;
(3) according to the varying strength rank requirement of riveting spiral shell product made from steel, select different open rollings, finishing temperature, the control finishing temperature is at 750~850 ℃;
(4) after the rolled piece finish to gauge immediately through 1~10 second cooling, guarantee that eventually cold rear rolled piece temperature is between 550~700 ℃;
(5) after the rolled piece cooling on roller-way through 5~15 seconds air cooling, then arrive cold bed, until room temperature;
Described blank chemical component is: between the carbon content 0.10~0.20%; Silicone content is between 0.05~0.10%; Manganese content is between 0.05~1.00%; P and s content is below 0.04%.
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103706631A (en) * | 2013-12-31 | 2014-04-09 | 常州中钢精密锻材有限公司 | Novel rolling process of nickel-based alloy bar materials |
CN104100622A (en) * | 2013-04-08 | 2014-10-15 | 彭亮生 | Large-scale and high-intensity rivet connection pair and manufacturing method thereof |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6293343A (en) * | 1985-10-17 | 1987-04-28 | Daido Steel Co Ltd | Non-heattreated steel wire |
CN1706977A (en) * | 2004-06-10 | 2005-12-14 | 东北大学 | Production process of high-strength cold heading rivet and screw steel |
DE102006015834A1 (en) * | 2006-04-03 | 2007-10-04 | Köster & Co. GmbH | Weld bolts are made of a manganese- and silicon-containing steel alloy that has been cold-worked to increase its strength |
-
2012
- 2012-12-05 CN CN201210514384XA patent/CN102943201A/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6293343A (en) * | 1985-10-17 | 1987-04-28 | Daido Steel Co Ltd | Non-heattreated steel wire |
CN1706977A (en) * | 2004-06-10 | 2005-12-14 | 东北大学 | Production process of high-strength cold heading rivet and screw steel |
DE102006015834A1 (en) * | 2006-04-03 | 2007-10-04 | Köster & Co. GmbH | Weld bolts are made of a manganese- and silicon-containing steel alloy that has been cold-worked to increase its strength |
Non-Patent Citations (1)
Title |
---|
李壮等: "低成本高性能低碳铆螺钢的试验研究", 《沈阳航空航天大学学报》 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104100622A (en) * | 2013-04-08 | 2014-10-15 | 彭亮生 | Large-scale and high-intensity rivet connection pair and manufacturing method thereof |
CN103706631A (en) * | 2013-12-31 | 2014-04-09 | 常州中钢精密锻材有限公司 | Novel rolling process of nickel-based alloy bar materials |
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Application publication date: 20130227 |