CN1123722A - Process for high-strength prestressed steel wire - Google Patents

Abstract

The technology for producing high-strength prestressed steel wire includes such steps as pickling high-carbon steel bar No.75-80 in 10-25% diluted sulfuric acid at 55-65 deg.C for 25 mins to remove three layers of iron oxide, pickling in diluted phosphoric acid at 65-85 deg.C for 5-15 mins to form netted phosphated film, saponifying in soap solution (80 kg/cu.m water) at 45-50 deg.C and reducing diameter through rolling at least two times.

Description

Process for high-strength prestressed steel wire

The present invention relates to process for high-strength prestressed steel wire, particularly a kind of intensity of steel wire that improves reaches low loose method.

High-strength prestressed steel wire is a kind of building material that just grows up in recent years both at home and abroad, because it has the intensity height, loose low, volume is light, and tension is strong, low cost and other advantages, be widely used in reservoir dam, large-scale cement bridge, high pressure water transport pipe line, cement, electric pole, sleeper, large roof slab, industrial circles such as protection network and mine, culvert, oil field.

Producing at present the general technological process of adopting of high-tensile steel wires is: pickling, and------unwrapping wire---is coated with lubricant and---slightly pulls out for the first time and---be coated with lubricant and---slightly pull out-be coated with lubricant for the second time and---pull out slightly for the third time that------last volume---------essence is pulled out for the first time, and------essence is pulled out for the second time, and------essence is pulled out for the third time, and------unwrapping wire is put in storage in rolling to be coated with lubricant to be coated with lubricant in annealing by last volume---packing---in rolling in oven dry.Because of its multi-pass draw, die wear is serious, steel surface should be drawn damage, percent defective height, noise is big, pollution is heavy to coil heavy little (only more than 200 kilogram of dish is heavy), particularly because the high tempering processing, destroyed the mechanical performance of steel, be difficult to produce high strength (＞1570Mpa), low loose, big specification, the heavy compressor wire of deep bid.

Main purpose of the present invention improves the tensile strength of present homemade cold drawn wire exactly, adopts loose lowly, and disk track is big, need not intermediate annealing, continuously produces the production technology of high-strength prestressed steel wire.

The present invention cancels high-temperature annealing process in the draw, make full use of the mechanical performance and the physical property of ferrous materials, the chemical treatment operation is incorporated into the production technology of cold rolling high tensile steel wire, make its surface softening, alleviate and roll pad wear, utilize the big advantage of rolling mill practice drafts, reduce rolling pass, the disposable qualified products of producing.

Processing step of the present invention is: adopt select materials, pickling, phosphatization, saponification, cold rolling cold-drawing technology, 1. select 75#-80# high-carbon reinforcing bar for use, pickling in the pickling tube of preparation 10-25% dilute sulfuric acid, pickling temperature is 55 ℃-65 ℃, time is 25 minutes, makes three layers of iron oxide (FeO, Fe ₂O ₄, Fe ₂O ₃) once strip down from rebar surface; 2. do phosphatization and handle in the phosphoric acid,diluted salting liquid, acidity is about 20-50, and temperature is 65 ℃-85 ℃, and the time is 5 to 15 minutes, makes Steel Wire Surface form netted phosphating coat; 3. carry out saponification and handle, the concentration of saponification liquor is 80kg/m ³Water, temperature are 45 ℃-50 ℃, and the time is 5 to 15 minutes; 4. logical: as to cross at least two rolling mills and contract, carry out the mechanical stress elimination then or adopt the low temperature recovery annealing in process, produce the high strength reinforcement of wire through cold rolling.

The present invention has the characteristics such as intensity of steel wire height that technology advanced person, production stage are simple, produce.

Below processing step of the present invention is further described; It is raw material that the present invention selects 75#-80# high-carbon reinforcing bar for use, adopt the distortion of colding pressing of amount of calculation, the disposable tensile strength 〉=1570Mpa that produces, yield strength 〉=1300Mpa, percentage elongation δ 100 〉=4, stress relaxation≤3, the qualified high-strength prestressed steel wire of number of bends 〉=4, its technological process is, 1. pickling, because high-strength prestressed steel wire is to be raw material by high carbon steel, high carbon steel is in hot rolling technology processing, because redox reaction, produce oxide skin at steel material epidermis, directly influence lubricant effect, on the other hand, because oxide skin hardness is bigger, easily make steel surface cause blemish such as drawing the road, draw power is increased, and the die wear aggravation causes the draw difficulty, the iron scale of carbon steel, form by three layers, internal layer mainly is ferrous oxide (FeO), and the intermediate layer is the tri-iron tetroxide (Fe of magnetic ₃O ₄), extexine is di-iron trioxide (Fe ₂O ₃), after the steel material immersed sulfuric acid solution, the alkaline oxygenated iron sheet on steel material surface and sulfuric acid generation chemical reaction once stripped down three layers of iron oxide from rebar surface, and sulfuric acid concentration and temperature are the principal elements of decision pickling speed, improve H ₂SO ₄Concentration can be quickened acid cleaning process, reaches more than 30-50% but work as concentration, and acid cleaning process slows down on the contrary, owing to the purifying and the oxidation that surpass sulfuric acid after 30% when concentration are strengthened thereupon, at the undissolved purification membrane of the surperficial formation of steel material, has stoped SO ₄With the chemical reaction of metallic iron, if the temperature of sulfuric acid solution is brought up to 60 ℃ from 30 ℃, the pickling time has then reduced 5/6, and in practice, the concentration of sulfuric acid solution is generally 10-25%, and temperature is 55 ℃-65 ℃.Phosphatization and saponification are handled, material after the pickling is put into phosphate solution, carrying out alramenting handles, the lubricating process that matches with soap lye then, phosphating coat on the material surface after the phosphatization can adsorb the liquid soap of lubricate securely, guarantee that in process of tube plug drawing mill supply continuously is lubricated, and have good plasticity at zinc soap itself, can produce plastic deformation with material, and under the deformation temperature of draw, can keep chemical stability, and playing good lubrication, coefficient of friction is 0.08, when phosphate solution acidity is hanged down, phosphatization speed is slow, cross when low in addition phosphatization improper, when acidity is too high, although accelerated parkerizing process, but can quicken the dissolving of iron-based body, the solution iron ion is increased and influence the quality of phosphating coat, in production technology, phosphatic acidity is controlled at about 20-50, its temperature is controlled between 65 ℃-85 ℃, keeps 5 to 15 minutes in the material solution under these conditions, just can obtain desired phosphoric acid film.With the material after the phosphatization, after cleaning, directly put into the soap pond 5-15 minutes, after the saponification, the smooth film of one deck appears in material surface, and the amount of preparation of saponification liquor is at 1 meter ³Adding is industrial in the water, (aliphatic acid is more than 60% for civilian soap, free alkali is below 1%) 80kg, in the pond, add a certain amount of water during preparation, power adds soap and directly uses Steam Heating again, the soap pond add earlier join half water of liquor capacity, be heated to 55 ℃-60 ℃, put into the liquid soap for preparing again, and then water is added to specified altitude, stirring to stop heating, can use when temperature drops to 45 ℃-50 ℃.Material is through after the above-mentioned softening processing, case hardness obviously reduces, but the mechanical performance and the physical property of inherent quality do not change, tensile strength keeps initial value 931Mpa, material is placed on the rotating disc type pay off rack, tractive force with drawbench rotates, the tractive force of blooming mill is used as power by the 55KV motor, speed is 2.4 meter per seconds, with M8 steel undergauge to M7, tensile strength is increased to 1091Mpa, garden degree ± 0.15, two milling trains also are used as power by the 55KV motor, steel taper to M6 by M7, tensile strength reaches 13.50 ± 0.10, and finishing mill is made traction power by the 28KV motor, and steel taper to φ 5.3-5.4 by M6, roundness tolerance size ± 0.05, tensile strength surpasses 1500Mpa, and drawbench is used as power by the 28KV motor, and steel are by φ 5.0 ceramic wire-drawing dies, taper to φ 5.0 by φ 5.3, roundness tolerance 0.02, and eliminate stress by the machinery device that eliminates stress, also can adopt the low temperature recovery annealing in process to eliminate stress, to increase percentage elongation, admission machine is used as power by the 17KV buncher, drives the take-up pulley take-up, the packet receiving bundling.

Embodiment 1. first steps select for use the homemade 75# high-carbon reinforcing bar of direct φ 8 to make raw material, the dilute sulfuric acid of preparation 15% in pickling tube, heat to 60 ℃ by Boiler Steam, kept 25 minutes, at this moment three layers of iron oxide once strip down from rebar surface, second step, preparation phosphoric acid,diluted salting liquid in the phosphoric acid salt pond, acidity is 30, heat to 70 ℃, kept this temperature 10 minutes, make Steel Wire Surface form netted phosphating coat, in the 3rd step, in the saponification pond, prepare saponification liquor, concentration is every cubic metre of water 80kg, heat to 50 ℃, the time is 10 minutes, the 4th step, the blooming mill that is used as power by the 55KV motor carries out breaking down, to M7, at this moment tensile strength is increased to 1091Mpa with M8 steel undergauge, circularity ± 0.15, and then be rolled by two milling trains that the 55KV motor is used as power, steel taper to M6 by M7, and tensile strength reaches 1350 ± 0.10, with finishing mill steel are tapered to φ 5.3-5.4 by M6 again, roundness tolerance size ± 0.05, tensile strength surpasses 1500Mpa, by the ceramic wire-drawing die of φ 5.0, tapers to φ 5.0 by φ 5.3 at last, roundness tolerance 0.02, packet receiving bundling after the admission machine take-up.

Claims (1)

1. process for high-strength prestressed steel wire, employing is selected materials, pickling, phosphatization, saponification, cold rolling cold-drawing technology, it is characterized in that processing step is: 1. select 75#-80# high-carbon reinforcing bar for use, pickling in the pickling tube of preparation 10-25% dilute sulfuric acid, pickling temperature is 55 ℃-65 ℃, time is 25 minutes, makes three layers of iron oxide (FeO, Fe ₂O ₄, Fe ₂O ₃) once strip down from rebar surface; 2. do phosphatization and handle in the phosphoric acid,diluted salting liquid, acidity is about 20-50, and temperature is 65 ℃-85 ℃, and the time is 5 to 15 minutes, makes Steel Wire Surface form netted phosphating coat; 3. carry out saponification and handle, the concentration of saponification liquor is 80kg/m ³Water, temperature are 45 ℃-50 ℃, and the time is 5 to 15 minutes; 4. contract through cold rolling by at least two rolling mills, carry out the mechanical stress elimination then or adopt the low temperature recovery annealing in process, produce the high strength reinforcement of wire.