DE1124067B - Process for the production of unalloyed steel wire and strip steel with high elastic properties - Google Patents

Description

GERMAN

PATENT OFFICE

F 29019 VIa / 18c

REGISTRATION DATE: JULY 25, 1959

NOTICE
THE REGISTRATION
AND ISSUE OF
EDITORIAL: FEB 22, RU AR 1962

It is well known that steel wires with high elastic properties are used for many purposes, For example, as spring wires, prestressed concrete wires and the like. One understands by high elastic properties the ratio of the position of the 0.01 limit and the 0.2 limit to the tensile strength. With the spring and prestressed concrete wires mentioned, this ratio must be as high as possible, so that the operating tension remains in the full elastic range.

It is known that one can achieve a high elasticity characterized in patented drawn or cold-rolled steel wire, subjecting the steel wire after drawing an annealing treatment consisting in heating at temperatures of 170-420 ⁰ C. This treatment increases the elastic limit (0.01 limit) of drawn wires by over 100 ^fl / o and the 0.2 limit by about 50 ° / o. The effect of this tempering treatment can be increased by exercising it under tension.

It is also known that with patented drawn or cold rolled steels even after this tempering treatment is the transition from the elastic to the plastic range under high loads not suddenly, d. H. with a pronounced elasticity or yield point, but occurs gradually. As a result, ζ. Β. in the case of prestressed concrete wires, these drawn and tempered steels have a somewhat have a lower creep limit than, for example, finally tempered steels, which due to their martensitic Structural condition have a very high elasticity and yield strength ratio.

Finally, it is known that as a heat treatment for the production of steel wires, In addition to patenting or final remuneration, also apply an intermediate level remuneration that results in a structural condition which is clearly different from the structures that one obtained by the first two heat treatment processes. So is one in two passes Intermediate tempering of unalloyed and alloyed strips, wires, etc. has become known, the steel in the first working step so quickly in an area of increased austenite resistance is transferred that the austenitic state is retained and in a subsequent second operation is kept so long at such a high temperature that a complete Conversion into an intermediate structure takes place. It should be advantageous to use the steel in the first step briefly in a bath of oil, water more watery

Method of manufacture

of unalloyed steel wire and strip steel

with high elastic properties

Applicant:

Feiten & Guilleaume Carlswerk

Iron and steel stock corporation,

Cologne-Mülheim, Schanzenstr. 28

Dipl.-Ing. Wilhelm Schull

and Dr.-Ing. Fritz Schwier, Cologne-Dellbrück,

have been named as inventors

Solution of caustic soda or table salt at room temperature, accelerated by a temperature in the range To deter martensite formation. With thin wires, especially thin ribbons, there should be in these, the cooling in baths with a high quenching effect is so fast that it does after a short dwell time in the quenching bath, the

. accelerated martensite formation is achieved and undesired martensite formation is not or It is difficult to avoid the cooling in a compressed air flow, its deterrent effect by changing the flow rate or, if necessary, by adding Water vapor is regulated. To regulate the quenching process and / or to adjust and comply The temperature of the transformation in the second stage is electroinductive heating used.

In the wires and tapes treated by this method, however, neither the Perlite and avoid the formation of martensite with certainty. When applying the procedure on For wires or strips made of unalloyed steel, the process is limited to steels with a carbon content of about 0.6% in order to suppress the conversion to pearlite during quenching in the heat bath to be able to.

Investigations into the applicability of this heat treatment in the production of unalloyed Drawn or cold rolled steels have also been shown to compare the interstage tempering to the usual process of patenting

209 510/295

Claims (1)

3 4 does not lead to the desired success, since the tension loss in the creep test in% of the specified quality values of the intermediate tempered initial tension after 1000 hours with an initial drawn steel wire or cold-rolled strip tension of well below those normally patented and 0.55-ög = 1.2 % of drawn or cold-rolled wires or strips 5 are 0.65 · σ «= 3.1%. This is 'to _7ς _ Jq _0, conditions and twists, the high for the _ qualitative evaluation of a steel wire or steel ⁰ ^' mainly on the number of bending _η ^a B ~~ ^y H ^{/ o} band by experts throughout In contrast, the same wire of 7.0 mm was considered to be decisive. The intrinsic strength - 10 diameter, but normally patented and drawn to a shaft including the elastic yield point strength of 173 kg / mm ² , and the yield point (0.01 and 0.2 limit) result in a loss of tension in the same creep test speak of the values that are usual with patented and with an initial tension of drawn wires or cold-rolled strips (cf. magazine »Stahl und ₁₅ 0.55 ■ σ _β - 1.8% Eisen«, No. 2, 1950, Pp. 52 to 57). 0.65 · a _B ■ = 5.2% The invention is based on a method for 0.75 · σ β - 10.7% production of unalloyed steel wire and strip steel 0.85 · a _B - 17.8% with high elastic properties under Apply cold deformation by means of drawing or rolling, 20 The yield point (0.2 limit) was 156 kg / mm ² the steel previously subjected to a homogenization The elastic limit (0.01 limit) Annealing at a _{temperature above Ac 3} was 131 kg / mm ² subjected and subsequently quenched as well after cold forming under tensile stress. and suggests quenching as 25 Carry out intermediate level remuneration and the ab- 1. Process for the production of unalloyed closing tempering immediately after the last steel wire and steel strip with high elastic Cold forming in the same operation with Tempe properties using a cold forming temperatures between 150 and 400 ° C and action by means of drawing or rolling, the strong tensile stress. ₃₀ steel was previously involved in a homogenization annealing According to the invention, the tensile stress is subjected to temperatures _{above Ac 3 for this purpose} preferably chosen so large that another, ge and then quenched as well as after lower cross-sectional decrease under the influence of cold working tempered under tensile stress Tensile stress and the increased temperature takes place. is characterized in that the deterrent The tensile stress is advantageously carried out between 35 ken as an intermediate stage 35 and 60% of the tensile strength of the drawn material. and the final tempering immediately after The tempering treatment itself can be performed by electrical cold working in the same working Resistance heating, induction heating or running at temperatures between 150 and 400 ° C z. B. in lead or salt baths. under the action of strong tensile stress According to another feature of the invention, 40 may be assumed. it is particularly in the case of prestressed concrete wires or strips. 2. Method according to claim 1, characterized thereby The advantage is that it indicates immediately before starting that the tensile stress is selected to be so great under tensile stress with notches or indentations that a further, slight transverse oversight, d. H. to profile them in order to reduce their adhesion in the section under the influence of the tensile concrete to increase. 45 tion and the increased temperature takes place. The 3. The method according to claim 2, thereby targeted with the method according to the invention Quality values are indicated in the following by an example that the tensile stress between game explained: about 35 to 60% of the tensile strength of the drawn material An intermediary according to the procedure described. step-hardened and then from 8.0 mm to 50 4. The method according to claim 1 to 3, characterized 7.0 mm pulled in one step and marked that the steel wires or bands Left steel wire with a C content of 0.86% immediately before tempering under tension had z. B. the following physical properties: be provided with notches or indentations. Tensile strength 173 kg / mm ² according to guidelines: Yield strength (0.2 limit) .160kgW _{Deutsdie Patent} i _el | _{v 1800 V} Ia / 18c (loading Elastic limit (0.01 limit) 156 kg / mm ² announced on 4.1953); Elongation at break (1 = 10 · d) .. 7% »Industrie-Anzeiger«, 79th year (1957), no. 84, Necking 37% S. 1261; Bends (D = 5 · d) 7 60 "Steel and Iron", 1950, pp. 52 to 57. © 209 510/295 2.62