DD224619A1 - METHOD FOR PRODUCING STEEL WIRE WITH INCREASED BREAKING TERMINATION - Google Patents

Abstract

The invention relates to a method for the production of carbon steel carbon steel with increased elongation at break and defined strength values. The aim of the invention is to achieve the required final properties of drawn steel wires without heat treatment in subsequent glazing units and / or without additional devices and work steps by redetermining the method steps of cold forming. According to the invention, the total deformation to achieve the finished wire cross-section is divided into defined Einzelquerschnittsabtnahmen that at 65-85% of Gesamtumformstufen, 88-95% of the intended total cross-section decrease processed and set at least 90% of the required ultimate strength and at least 80% of the required elongation at break. The further draw forming to achieve the final diameter while maintaining the required elongation at break of greater than 3.5% is carried out by one or more Einzelumformstufen, the respectively required final properties are set.

Description

Process for producing steel wire with increased elongation at break

Field of application of the invention

The invention relates to a method for the production of steel wire with increased elongation at break in conjunction with defined strength values,

Characteristic of the known solutions

The production of steel wire with increased elongation at break and defined strength values is usually carried out by cold forming mitteis pulling with subsequent heat treatment in the run or in annealing heads · It is to reduce the wire cross-section or to achieve certain Werkst offkennwerte the drawn finished wire, the total cross-section decrease when pulling in the same divided large, progressively decreasing or increasing Sinzel cross-section decreases'. It is also known that in the last pass work is carried out with a cross-section reduction deviating from the preceding individual cross-section decreases. It is also an optimization of the individual air intake decrease depending on the power supply of the drive motors to achieve a uniform Snergieausnutsung without special consideration of these influences on the mechanical-technological properties of Perti ~ wire it is applied.

Characteristic of the cold forming by drawing is the increase in strength and elongation at break with each individual forming step, resulting in a necessary heat treatment to achieve an increased elongation at break required.

3s, methods are also known which attempt to achieve the desired property improvements, in particular for achieving increased elongation at break values, without tempering annealing, while maintaining the required strength values, with the aid of cold forming followed by process steps and additional equipment.

For example, the manufacture of concrete pipe wire with a diameter of 6.3 mm has hitherto been solved by pretreating an unalloyed steel wire with a carbon content of 0.60-0.69% and a starting diameter of 10 mm for drawing, then drawing it to the final diameter. subsequently heat-treated and provided with temporary corrosion protection.

The above-mentioned methods have the disadvantage that, in order to achieve high elongation at break values while ensuring defined levels of peatness and / or elasticity, heat treatment processes must be followed by cold forming. This, in addition to additional energy requirements, means loss of material and additional labor for the heat treatment. Due to the empirical plaguing of the individual conversion steps or their adaptation to the machine equipment, it is not possible to achieve the desired quality features exclusively by pulling. Another disadvantage of said method is the necessary use of additional devices and operations with technologically only consuming controllable precision settings of devices and with only partially reproducible Werkst offkennwerten the pertigdraht »

Object of the invention

The aim of the invention is to avoid the drawbacks of the prior art by applying a method that the required. end properties on drawn steel wire without heat treatment in subsequent annealing devices and / or without additional devices and working steps by making it possible to carry out the cold forming process steps.

Presentation of the article of the invention

The invention has for its object to perform the required mechanical-technological properties adapted cold forming only by pulling, these end igensσhaften be achieved without additional Uaοübehandlang and / or devices, or other Verfahrenssehrit te «

According to the invention, the object is achieved in that after the conventional preparation of unalloyed steel wire with 0.05 - 0.85 % carbon content for drawing and a subsequent cold forming on conventional wire drawing machines with conventional drawing tools the necessary total deformation to achieve the final diameter in different sizes but precisely defined Sinzelquerschnittsabnahmen is split "surprisingly, in fact, that a certain Enae ~ diameter can be produced with a defined 'strength at the same time increased elongation values when operating at the drawing forming with a process regime different high Einzelquerschnitt3abnahmen in certain Heihenfolge, so that a subsequent V / heat treatment or other work steps with and without additional device are not necessary · For this purpose, the total deformation to achieve the J'ertigdrahtendquerschnittes in defined Einzelquersch nitts decreased so divided that at 65 - will be 95% of the intended total querschnittsabnähme processed and at least SO% of the desired elongation at break set · - s the total umformstuf s, 38 35% preferably 75 ~ _f?

The further Ziehumformung to achieve the final diameter with insignificant increase in strength but increasing elongation fraction greater than 3.5 % is carried out by one or more Einzelumformstufen, the respectively required final properties were set.

Application example

1. A steel wire with increased elongation at break and a diameter of 6.3 shall now be manufactured with the following characteristics:

Tensile strength R ^ : 1300 - 1500 IiPa Yield point ^ n O 2 : 1070 - 1350 iiPa elastic «yield strength R _{Λ η} . _Λ P UjUi • "* 820 MPa Elongation at break A. _Q :> 4.5 % Fracture necking Z   ^ * 35% Mindestverwindezahl without breakage * 5

The output wire of 10 mm diameter carbon steel with 0.60 - 0.69% carbon content is heat-treated in a conventional manner, phosphated and limed and then on a known Yiererkombination the drawing machines UDZSA 5000/1 with bending winder in the following steps at a Drawing speed of 67 m / min or 95 m / min.formed,

1st pull 12.2 - 17.2 ^ b Single cross section decrease

2, train 18.3 - 23.4 % single cross section 3 »train 30.2 - 31.2 % single cross section 4 · train 14.2 - 15.4 % single cross section decrease

After 3 times of draft (75 % of the number of drawing stages and at least 89% of the total cross- section decrease ), the wire has an average strength of 1360 MBa., which corresponds to 98 % of the final strength.

When the tension is reached, an average tensile strength of 1390 IiIPa and an expansion increase in relation to the elongation at break after the 3-pass of 15-20 % are achieved to a final value of -5 % . All required characteristic values are guaranteed reproducible »

2. Anticipated and vorpatentierter wire having a carbon content of 0.07 to 0 ^ 1% and a diameter of 3 »6 mm is to be cold drawn to a final diameter of 1.5 mm" The 3ndfestigkeit R may qq at an elongation of at least & * 4% and a constriction Z of at least 45 % 1250 MPa not higher than and not lower than 1100 I ¹ IPa *

These requirements can be realized by the drawing regime with the following drawing stages at a drawing speed of 180 m / min:

Number of drawing stages - - 1 2 3 4 .5 Diameter mm 3,6 3,05 2,55 2,2 1,36 1,66 1,5 Sinzelquerschnitt sab-

% - 23 30 26 28 20 18

Overall cross-section decrease% - 28 49.7 62.3 73.2 78.7 82.64

After the 5-pass (83% of the draw step number and 95 % of the total cross-section reduction), the wire has a tenacity of 1077 MPa, which corresponds to 98 % of the required final strength and an average elongation at break of 4.3 % . This is 96 % of the elongation at break value. After the 6th pass, the required bond strength of 1100-1250 IvIPa and an elongation at break of on average 5.0 % are achieved.

Claims (1)

invention claim Method for the production of steel wire with 0.05 - 0.85 % carbon content with increased elongation at break and defined strength by cold forming, in particular by drawing on conventional wire drawing machines with conventional drawing tools, characterized in that the total deformation to achieve the finished wire cross section is divided into defined Einaelquerschnittsabtnahmen that at 65-85%, preferably 75 %, of the total forming steps, 88-95 % of the intended overall cross-section decreases and at least 90%, preferably 95-98 % of the required ultimate strength and at least 80 % of the required elongation at break are set and that the further draw-forming to achieve de3 Final diameter when adhering to the required elongation at break of greater than 3.5% by one or more Einzelumformstufen done, the respective required end properties are set.