A method of manufacturing a heat-treated rod reinforcing steel

 

(57) Abstract:

The invention relates to ferrous metallurgy, in particular to the manufacture of heat-treated rod reinforcing steel in small sections with the use of heat rolling heat, and can be used for thermal hardening of rent in the flow of merchant bar mills. The technical result of the invention to provide high strength and plastic characteristics of the steels that do not contain costly and scarce alloying elements, as well as the ability to manufacture high-strength heat-treated reinforcing steel in small profiles. The billet is heated to 1200C, laminates and using the heat rolling heat conducting recrystallization during 0,17 - 0,19 with 102030C and cyclic cooling of the surface during 0,85 - 0,95 with a number of cycles equal to two, interim and final tagrename surface temperature below the Ac1 point, and final cooling. table 1.

The invention relates to ferrous metallurgy, in particular to the manufacture of heat-treated rod reinforcing steel in small sections with the use of heat rolling heat, and can be used for thermal control is an example, a known method of thermal processing of metal, mostly bar reinforcement, using the heat of the rolling heat, including cyclic cooling of the surface during the time of 0.015 - 0.045)is D in each cycle with hypothermia surface below the point of the pipeline with a number of cycles equal to two, with intermediate annealing surface within 0.7 to 2.5 sec, and final annealing during 4,0 - 7,5 to temperatures rig point Mn, but below the Ac1 point, and final cooling, where D is the diameter of the rod, mm /1/.

Closest to the claimed method according to technical essence and the achieved positive results is the method of thermal processing of metal using heat rolling heat, including hot rolling, pre-cooling of roll up to temperatures of Ar3 + (20 - 50)oC with exposure (0,025 - 0,115)D, cyclic cooling surface over time (0,015 - 0,035)D with up to temperatures of Mn + (20 - 100)oC in each cycle when the number of cycles is not less than 2 interim and final tagrename surface to temperatures Ac1 - (20 - 100)oC and the final cooling, where D is the diameter of the roll in mm /2/.

The disadvantage of this method is the low level proccacia consumer properties on plain carbon steels, for example, article PS.

The task of the invention is the possibility of obtaining high strength and plastic characteristics of the steels that do not contain costly and scarce alloying elements such as Mn, Ni and others, as well as the ability to manufacture high-strength heat-treated reinforcing steel in shallow profiles (for example, N10, N12) after rolling with the separation strip.

This object is achieved in that in the known method of thermal processing of metal using heat rolling heating, including heating billets, her hot deformation and cyclic cooling surface with a number of cycles equal to two, interim and final tagrename surface temperature below the Ac1 point, and final cooling, according to the invention after deformation of metal hold the recrystallization of steel for 0,17 - 0,19 with at a temperature of 1020 30oC and cyclic cooling roll is carried out in the course of time 0,85 - 0,95 C.

It is found experimentally that for obtaining the fine grain structure and uniform distribution of perlite component to a greater depth on the diameter of the roll on plain carbon steels, it is necessary n the 0,19 with, when carrying out recrystallization of deformed austenite in a period of time less 0,17 with no time to fully complete recrystallization processes, which will lead, in the subsequent thermal hardening, to the folding of thermal and residual deformation stresses and, consequently, the violation of technological process rolling with padding (curvature of the roll, camber) due to uneven heat distribution over the cross section of the piece. To save the heat balance on the diameter of the roll and for high dispersion patterns of metal processing heat strengthening metal circular cooling should be no more than 0,95 s temperature end recrystallization processes not more than 1050oC, and to obtain the required strength characteristics at high plasticity cyclic cooling should be done at least 0,85 s temperature end recrystallization of deformed austenite is not less than 990oC.

The proposed method of thermal processing of reinforcing steel with specified set of, sequence of operations and the selection of intervals of the characteristic values in the specified range of their variations provide dostizheniya of plain carbon steels by creating technology, heat strengthening reinforcing steel small profile, including obtained by rolling with a separation strip.

This technical result is achieved by solving the problem on inventive step, for example, the choice of limits of time and recrystallization temperature of the metal after its deformation, as well as the limits of cyclic cooling roll that does not follow from the prior art.

The implementation of the method of manufacturing a rod of heat-treated reinforcing steel was carried out as follows.

Example. In section rolling shop of JSC "ZSMK" in mill 250-1 conducted pilot testing of the proposed method of manufacturing heat-treated rod reinforcement steel PS N10 industrial melting.

For this billet cross-section 100 x 100 was heated to a temperature of 1200 20oC, rolled on a continuous bar mill 250-1, conducted recrystallization of the steel during the time of 0.18 s at a temperature of 1030oC. Then spent cyclic cooling of the roll during the time of 0.90 with two loops and the intermediate annealing, and then perform the final heating the surface to a temperature of 590oC. Final cooling was carried out on the air.

On predlagaemy a temperature of 1020 30oC, time cyclic cooling in the claimed range of their changes beyond the boundary values. After the implementation of these modes were determined by tensile strength, yield strength and a five-fold elongation.

The results of industrial tests given in the table.

The table shows that the optimal method of manufacturing heat-treated reinforcing steel are the modes of examples 1 - 3.

The proposed method of thermal processing of reinforcing steel ensures the achievement of the technical result consists in providing strength and plastic characteristics of the steels is not due to the alloying elements, and by creating a process for heat treatment of steel. For example, from the data table shows that in the manufacture of heat-treated reinforcing steel on the proposed method obtained the maximum strength characteristics of the metal (tensile strength - 67,5 - 69,0 kgf/mm2yield strength - of 57.5 - 60.0 sec kgf/mm2) while maintaining high plasticity (24 per cent). Metal reinforced for modes that deviate from the proposed limits of the parameter values, has a reduced level of strength and plastic harano affects the technological process of hardening and resistance began to strain aging. These data are confirmed by an act of industrial tests.

The proposed method is industrially applicable in metallurgical enterprises with continuous light section mills and producing car for various purposes. For example, the use of this method in the manufacture of heat-treated rod rebar merchant bar mill 250-1 JSC "ZSMK" showed high efficiency technologies.

Sources of information

1. RF patent N 2025503, class C 21 D 1/02, 1994.

2. RF patent N 2081182, class C 21 D 1/02, 1997.

A method of manufacturing a heat-treated rod reinforcing steel, mainly small profiles using heat rolling heating, including heating billets, her hot deformation and cyclic cooling surface with a number of cycles equal to two, interim and final tagrename surface temperature below the Ac1 point, and final cooling, characterized in that after deformation of metal hold the recrystallization of steel for 0,17 - 0,19 with at 1020 30oC and cyclic cooling roll can be performed during 0,85 - 0,95 C.

 

Same patents:

The invention relates to metallurgy, in particular to the production of rebars periodic profile

The invention relates to metal forming, and more specifically to the drawing production, and can be used in the technological process of manufacturing of cold drawn copper products produced from continuously cast billets NLS)

The invention relates to metallurgy, in particular to the technology of wire from nodular cast iron, which combines high strength and plastic properties with resistance against corrosion

The invention relates to equipment for the heat treatment of metals and can be used in processes requiring fast heating and slow cooling at a given speed, in particular for spheroidizing and recrystallization annealing calibrated steel in coils

The invention relates to equipment for thermal processing of metals and alloys and can be preferably used for annealing, normalizing calibrated steel from mikrotechna temperature range (MCI) and thermolysine (quenching and tempering) calibrated steel, intended for the manufacture of high-strength fasteners by the method of cold forming processes (GHOSH)

The invention relates to equipment for thermal processing of metals and alloys and can be used mainly for recrystallization and spheroidizing annealing and quenching calibrated steel from mikrotechna temperature range (MCI), used in the manufacture of high-strength fasteners by the method of cold forming processes (GHOSH) without final heat treatment

The invention relates to ferrous metallurgy, in particular to the manufacture of sortoprokatnoe, leading to changes in the metal structure, and can be used in the manufacture of heat-treated billet rod, when hot rolling and stamping combined with quenching in air directly from the hot temperatures of the processing pressure
The invention relates to the use in the production of shaped profiles of high precision small cross-sectional area (up to 100 mm2)

The invention relates to metallurgy, and more specifically to a method of heat treatment for removing hydrogen and increase the plasticity in steels, mainly bainite class

The invention relates to ferrous metallurgy, in particular to thermal processing of reinforcing steel using heat rolling heat, and can be used for thermal hardening of rent in the flow of merchant bar mills

The invention relates to the field of the fourth redistribution metal hot stamping and can be used on metal and machine-building plants

The invention relates to rolling production and can be used for the rolling of wire rod on the bar mills

The invention relates to heat treatment of forgings for rings, in particular the production of protective atmosphere in structural annealing

The invention relates to a heat treatment, in particular to assemblies intended for thermal processing mill rolls, and structural elements such aggregates, and can be used in mechanical engineering

The invention relates to a heat treatment, in particular to assemblies intended for thermal processing mill rolls, and structural elements such aggregates, and can be used in mechanical engineering

The invention relates to a heat treatment, in particular to assemblies intended for thermal processing mill rolls, and structural elements such aggregates, and can be used in mechanical engineering

The invention relates to furnaces for heating the calcined product of amorphous carbon before impregnation pitch

The invention relates to the metallurgy of iron, in particular to methods and furnaces low - and non-oxidizing heating of steel products such as wire, and can be used in metallurgical and machine-building plants
Up!