Method of manufacturing spheroidizing rolled low-carbon steel for cold massive forming geometrically-complex fasteners

 

(57) Abstract:

The invention relates to the field of metallurgy, in particular to the production of rolled low-carbon steel for cold massive forming geometrically-complex fasteners particularly complex form. The technical result of the invention is to provide a structure of the rolled that provide sustainable conditions for cold massive forming geometrically-complex high-strength fasteners while providing high performance technological ductility and toughness of steel. To achieve a technical result smelted steel in the electric furnace, conduct secondary treatment, casting molds with stream protection, hot rolling of the ingot and receiving the workpiece and subsequent controlled rolling, winding rolled in riots, calibration of rental with deformation rate of 15-20% and spheroidizing annealing. Smelted steel with the following ratio of components, wt.%: carbon 0,27-0,32, manganese between 0.30 to 0.65, silicon from 0.01 to 0.17, chrome 0,01-0,25, sulfur of 0,005 0,020, niobium 0,005-0,02, calcium 0,001-0,010 rest of the hardware at performance ratios: 12/S - Mn/0,03 20; Sa/S 0,065. Microalloying of steel niobium inhibits the processes of recrystal rolling on the existing equipment and provides for the formation of fine patterns. Spheroidizing annealing lead by the speed of heat in microtechno temperature range of cold metal followed by controlled cooling in the temperature range 650-S with speeds of 1.0 to 1.5 C/min, and further cooled in a heat chamber at room temperature 100-150C, which reduces the duration of the process of spheroidizing 5-10 times. 1 C.p. f-crystals.

The invention relates to the field of metallurgy, in particular to the production of rolled low-carbon steel for cold massive forming geometrically-complex fasteners particularly complex form. Known structural steel containing, wt.%: carbon 0,17 of 0.20%, manganese of 0.65-10%, silicon 0,17-0,37%, chromium 0,55-0,70%, vanadium of 0.05-0.08%, niobium 0,02-0,04%, the rest of the iron in the following ratio, wt.%: (USSR author's certificate 1703709 from 07.01.1992,, bull. NO. 1, P 22 WITH 38/26).

The most important requirement of rolled steel of low carbon steel for cold massive forming geometrically-complex fasteners particularly complex form, is, on the one hand, the high technological plasticity and low coefficient of strain hardening in the state of delivery and, with another hundred and rolled it takes a long repartition, includes the following operations: smelting, hot rolling, spheroidizing annealing, calibration. The task of providing the necessary mechanical properties and performance of technological plasticity and low coefficient of strain hardening of the metal in the state of delivery currently successfully resolved through a number of techniques used at different stages of production are:

The closest analogue to the claimed invention is a method of producing rolled low-carbon steel for cold massive forming geometrically-complex fasteners including steel smelting in the electric furnace, secondary treatment, casting molds, hot rolling the ingot to receive the workpiece and cooling (EN 2042734 C1, With 22 38/54, 27.08.1995).

The basis of the invention is the task of the development of the steel of increased deformability and production way it rolled. The technical result of the invention is to provide a structure of the rolled guaranteeing the rational conditions of cold massive forming geometrically-complex fasteners.

To achieve a technical result in the known method ¾ mounting parts, includes steel smelting in the electric furnace, secondary treatment, casting molds, hot rolling the ingot to obtain blanks, smelted steel in the following ratio, wt.%:

carbon 0,27-0,32

manganese between 0.30 to 0.65

silicon, from 0.01 to 0.17

chrome 0,01-0,25

sera of 0,005 0,020

niobium 0,005-0,02

calcium 0,001-0,010

iron rest

When performing correlations

after hot rolling carrying cold deformation calibration with deformation rate of 15-20% and spheroidizing annealing, cold-formed workpiece by high-speed induction in microtechno range of temperatures and followed by controlled cooling in the temperature range 650-S with speeds of 1.0 to 1.5 C/min, and further cooling in a heat chamber at room temperature 100-150C to reduce the duration of the annealing process. When casting molds protect the jet of metal.

Given the combination of alloying elements (p. 1) allow to get in the proposed steel rod with a diameter up to 25 mm) after rapid annealing homogeneous spheroidizing structure with a favorable combination of strength and plastic which provide fine grain structure, that will increase as the level of its strength, and to provide a given level of ductility. While niobium manages the processes in the austenitic region (determines the tendency to grain growth of austenite, stabilizes the structure during thermomechanical processing, increases the temperature of recrystallization and, consequently, affects the character --transformation. Niobium also contributes to hardening of the steel during thermolysine. The upper limit of the content of carbon (0.32 per cent), niobium (0,02%) due to the need to ensure the required level of ductility of steel, and the bottom respectively of 0.27%, 0.005% and provide the required strength level of the steel.

Manganese and chromium are used, on the one hand, as a solid solution hardeners, on the other hand, as elements, greatly increasing the stability of the supercooled austenite steel. The upper levels of manganese - 0.65% chromium, 0.25% is determined by the need to ensure the required level of ductility of steel, and the lower - 0.30% and 0.01%, respectively, of the need to ensure the required level of strength of the steel.

Silicon belongs to territooriumil elements. The lower limit for silicon - 0,01% - driven by technology raseleni Sulfur determines the level of ductility of steel. The upper limit (0,020%) due to the necessity of obtaining a given level of ductility and toughness of steel, and the lower limit (0,005%) - questions-tech production.

Calcium is an element, modifying nonmetallic inclusions. The upper limit (0,010%), as in the case of sulfur caused by the necessity of obtaining a given level of ductility and toughness of steel, and the lower (0.001%) limit - questions-tech production.

Relations define the conditions ensure the specified characteristics of plasticity and proclaimeth cold steel at the drop-forging of geometrically-complex fasteners.

An example of the method.

Smelting of low carbon steel of the following composition: carbon - 0,30%, manganese - 0,45%, silicon - 0,10%, chromium - 0,20%, sulfur - 0,011%, niobium - 0,012%, calcium - 0,001%, is produced in shaft furnace “Fuchs”. For guaranteed low nitrogen content developed special technology, comprising: melt blending a liquid cast iron up to 40% of the total volume of the mixture. Oxidative period provides a high rate of oxidation of carbon within 0,05-0,07 %/min electric mode involves shutting off the furnace when the carbon content of 0.2-0.4 per cent above the lower is d ferroalloys, steel treatment to remove non-metallic inclusions are produced at the ladle furnace equipped with an electric heating system or hinotori. The temperature of the steel before casting on 60 DEGREES above the liquidus temperature of the brand. Casting is done in extended upward moulds. The mass of the ingot a 7.85 so To ensure a low content of nitrogen in the casting is the protection of the jet of metal with argon through a special ring device. Heating of the ingots in the blooming shop is regenerative wells before the temperature started rolling 1250-S. Rolling ingots produced at the blooming mill (mill 1300) and then on a continuous billet mill on the billet cross section 100100 mm For removing the formed during heating of ingots de-carbonized layer of the workpiece are subjected to abrasive blasting." Then he made hot rolling the resulting workpiece on a wire mill 150 or small-section mill 250 in diameters from 5.5 to 23 mm in coils. To ensure the value of de-carbonized layer is not more than 1% of the diameter of the limited rate of billets from the furnace is not less than 100 t/h for 150 mill and at least 56 t/h to 250 mill. The onset temperature rolling of billets 1220-S for mill 250 and 1270-S for 150 mill. Hot procw riots. Followed by pickling hot-rolled steel in sulfuric acid solution (concentration of 180-200 g/l) at a temperature of 80C for 30 min, followed by the application podmazochnaja coverage. Followed by cold deformation calibration with deformation of 15-20% and spheroidizing annealing, including high-speed induction in microtechno temperature range (ACl+10-30C) of cold metal followed by controlled cooling in the temperature range 650-S, with speeds of 1.0 to 1.5 C/min, and further cooled in a heat chamber at room temperature 100-150C, which reduces the duration of the process of spheroidizing 5-10 times.

The execution ratio of the alloying elements helped to provide the required level of ductility of steel directly in the hot rolled condition level =28% and the level of cold precipitation sample with a diameter of 20 mm to 75% of the height.

when the manganese content is 0.45% of carbon - 0,30%

when the sulfur - 0,011%, calcium - 0,001%.

The introduction of the proposed method of production of rolled low-carbon steel high-stanoevska provides reception spheroidizing patterns rolled, guaranteeing the production of rolled low-carbon steel for cold massive forming geometrically-complex fasteners, includes steel smelting in the electric furnace, secondary treatment, casting molds, hot rolling the ingot to receive the workpiece and cooling, characterized in that the smelted steel in the following ratio, wt.%:

Carbon 0,27-0,32

Manganese between 0.30 to 0.65

Silicon, from 0.01 to 0.17

Chrome 0,01-0,25

Sera of 0,005 0,020

Niobium 0,005-0,02

Calcium 0,001-0,010

Iron Rest

when performing correlations

12/S - MP/0,03 20;

Ca/S 0,065,

where C is carbon;

MP - manganese;

CA - calcium;

S - sulfur

after hot rolling carrying cold deformation calibration with deformation rate of 15-20% and spheroidizing annealing, cold-formed workpiece by high-speed induction in microtechno range of temperatures and followed by controlled cooling in the temperature range 650-S with speeds of 1.0 to 1.5 C/min, and further cooling in a heat chamber at room temperature 100-150C to reduce the duration of the annealing process.

2. The method according to p. 1, characterized in that the casting molds protect the jet of metal.

 

Same patents:

The invention relates to the field of metallurgy, in particular to the production of rolled low-carbon steel for cold massive forming geometrically-complex fasteners

The invention relates to the field of metallurgy, in particular to the production of rolled low-carbon steel for cold massive forming fasteners particularly complex form

The invention relates to the field of metallurgy, in particular to the production of rolled low-carbon steel for cold massive forming fasteners particularly complex form

Rail steel // 2224041
The invention relates to ferrous metallurgy, in particular to the production of steel for rails

The invention relates to ferrous metallurgy, in particular to alloyed steels for steel products, and can be used in the production of gas and oil pipelines

The invention relates to ferrous metallurgy and can be used in the disc brake device of the cars and other vehicles

The invention relates to rolling production, particularly modes of rolling strips of low-alloy steels in continuous broadband mill

The invention relates to metal finish the wire and to a method of manufacturing the wire

The invention relates to metallurgy and can be used in the manufacture of welded hot rolled bar reinforcement class AS for concrete structures

The invention relates to high-strength steel and its manufacture

The invention relates to the field of metallurgy, in particular to the production of rolled low-carbon steel for cold massive forming geometrically-complex fasteners

The invention relates to the field of metallurgy, in particular to the production of rolled low-carbon steel for cold massive forming fasteners particularly complex form

The invention relates to the field of metallurgy, in particular to the production of rolled low-carbon steel for cold massive forming fasteners particularly complex form

The invention relates to the field of metallurgy, in particular to the production of long-rolled products of boron steel for cold massive forming of high-strength fasteners particularly complex form

The invention relates to the field of metallurgy, in particular to the production of long-rolled products of boron steel for cold massive forming of high-strength fasteners

The invention relates to the field of metallurgy, in particular to the production of long-rolled products of boron steel for cold massive forming of high-strength fasteners particularly complex form
The invention relates to the field of metallurgy, in particular to the production of long-rolled products of boron steel for cold massive forming of high-strength fasteners particularly complex form

The invention relates to the production of steel pipes by the method of hot deformation and can most effectively be used in the manufacture of pipes of alloy steels for steam boilers and pipelines
The invention relates to the field of metal products for industrial use, namely, metal wire

The invention relates to the field of metallurgy, in particular to the production of rolled round cross-section for subsequent drawing

FIELD: rolled tube production, namely method for making pilger mill mandrels from heat resistant steel for rolling hot rolled tubes.

SUBSTANCE: method for making mandrels used for rolling hot rolled tubes with large and mean diameters in range 273-550mm comprises steps of casting ingots of hear resistant steel; forging cylindrical solid or hollow blanks, roughly working of them, performing heat treatment and finishing mandrels at forming conicity 1 - 2 mm on length of their working portion while taking into account designed linear expansion coefficient during rolling process; determining diameter size by means of expression δ = dn - Δ/1 + α·t. One portion of mandrel from lock along length of half of working portion of mandrel is in the form of cone with diameters of cone bases determined form given expression and second portion is in the form of cylinder or truncated cone whose diameters are determined according to next expression

EFFECT: lowered lengthwise thickness difference of tubes.

3 cl, 1 dwg, 1 tbl

Up!