Round-profiled rolled iron from medium-carbon high-plasticity steel for cold die forging of high-strength especially high-profiled fastening members

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from medium-carbon high-plasticity steel composed of, wt %: carbon 0.27-0.32, manganese 0.30-0.50, silicon 0.01-0.37, chromium 0.01-0.25, sulfur 0.005-0.020, niobium 0.005-0.02, calcium 0.001-0.010, iron and unavoidable impurities - the balance. When following relationships are fulfilled: 12/C-Mn/0.03 ≥ 20, Ca/S ≥ 0.065, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 80% grainy perlite; effective grain size 5-10 points; diameter 10-30 mm; carbon-free layer not exceeding 1.5% diameter; cold setting value at least 1/3 height; point of maximum load not higher than 620 MPa; relative elongation at least 18%; and relative contraction at least 55%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously ensured improved characteristics of in-process plasticity and low level of stray hardening.

 

The invention relates to the field of metallurgy, in particular to the production of rolled, round, sredneuglerodistoj highly ductile steels for cold massive forming fasteners particularly complex form.

Known rolled round of micro steel containing carbon and alloying elements having a defined structure, such as cold-deformed martensite, a tensile strength of not less than 1800 MPa, and the wire diameter is 0.1-0.5 mm [1].

Famous bars, round of medium-carbon steel containing (wt.%): carbon 0,17 of 0.20%, si 0,17-0,37%, manganese, of 0.65 to 1.00%, chromium 0,55-0,70%, vanadium of 0.05-0.08%, niobium 0,02-0,04%, iron rest, when the ratio (chrome/carbon)vanadium/niobium)2=16,4-65,9 [2].

Closest to the technical essence and the achieved effect of the present invention is rolled, round, steel, containing (wt.%): carbon 0.18-0.22%, manganese 0.27-0.67%, silicon 0,17-0,37%, vanadium of 0.05-0.10%niobium, 0.01 to 0.04%, the rest is iron in the following ratio/, wt.%: 6V+8Nb≥ 0.56 and 100000VNb28.0 [3]. The disadvantages of the known fact that at a relatively high level of variation in the carbon content is not taken into account the protection factor of boron from binding in the nitrides that will not allow you to get increased hardenability characteristics.

C is the summer residence of the invention is the provision of efficient conditions for cold massive forming geometrically-complex fasteners while providing uniform mechanical properties across the section of the car and elevated characteristics of technological plasticity

The most important requirement of rolled steel, round, flexible medium-carbon steel for cold massive forming 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, on the other hand, the ability to provide the specified level of consumer properties.

The problem is solved by the fact that known rolled, round, flexible medium-carbon steel having a specified structure, ultimate strength and hardness, according to the invention, made of steel, with the following ratio of components, wt.%:

carbon 0.27-0.32

manganese 0.30-0.65

silicon 0.01-0.37

chrome 0.01-0.25

sulfur 0.005-0.020

niobium 0.005-0.02

calcium 0.001-0.010

iron and

inevitable impurities else

And:

the maximum score of contamination of steel, non-metallic inclusions in sulfides, oxides, silicates and nitrides of not greater than 3 points for each type of inclusions, car has a homogeneous spheroidizing structure in length, consisting of not less than 80% granular perlite, the amount of the actual grain - 5-10 point, iameter wire is from 10 to 30 mm, has a de-carbonized layer is not more than 1.5% of the diameter, the amount of cold upsetting of not less than 1/3 of the height, ultimate strength of not more than 620 MPa, elongation not less than 18%, the relative narrowing of not less than 55%.

Given the combination of alloying elements (1) allow to obtain in the finished product (bolt, nut, stud diameter up to 23 mm), post-cold massive forming a homogeneous fine structure of martensite leave with a favorable combination of strength and ductility.

Carbon and carbonitrides elements (niobium) are entered into the composition of this steel to ensure a fine grain structure, which will increase as the level of its strength, and to provide a given level of ductility. While niobium control processes in austenitic region (determines the tendency to grain growth of austenite, stabilizes the structure during thermomechanical processing, increases the temperature of recrystallization and as a consequence affects the character γ -α -transformation. Niobium also contributes to hardening of the steel during thermolysine. The upper limit of the content of carbon (0.32%), niobium (0.02%) due to the need to ensure the required level of ductility of steel, and the bottom, respectively, 0.27%, 0.005%, providing the required strength level of the steel.

Manganese is used, on the one hand, as a solid solution hardener, on the other hand, as an element, substantially increasing the stability of the supercooled austenite. The upper levels of manganese - 0.65% - determined by the need to ensure the required level of ductility of steel, and the lower - 0.30% - by the need to provide an appropriate level of strength of the steel.

Silicon belongs to territooriumil elements. The lower limit for silicon - 0.01% - caused by the deoxidation of steel. The silicon content higher than 0.17% will adversely affect the characteristics of ductility of steel.

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.

Ratios

define the conditions ensure the specified characteristics of plasticity and proclaimeth cold steel at the drop-forging of geometrically-complex crepe is mportant details.

Therefore, the claimed set of characteristics meets the criterion of "substantial differences".

Below is an example implementation of the present invention, not excluding other in the scope of the claims.

Smelting flexible medium-carbon steels are produced in shaft furnace “Fuchs”. For guaranteed low nitrogen content developed special technology, including melt blending 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 percent above the lower limit specified, dodavku the carbon produced without arcing. The temperature of the discharge from the furnace 1640-1680° C. Enter ferroalloys, steel treatment to remove non-metallic inclusions is made at the ladle furnace equipped with an electric heating system or hinotori. The temperature of the steel before casting on 60° C above the liquidus temperature of the brand. Casting is done in extended to the top of the mold. 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 in recuperation the x wells before the temperature started rolling 1250-1270° C. Rolling of ingots produced at the blooming mill (mill 1300) and then on a continuous billet mill on the billet cross section of 100× 100 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 1220-1240° (C) to 250 mill and 1270-1290° (C) to 150 mill. Hot rolling of the rolled finish at a temperature of 1000-1050° With, then rapid cooling to 880-900° C, followed by cooling to 300° and then winding the coils.

In the hot rolling get rolled diameter of 21 mm with the structure of granular perlite (99%), bezplatny layer depth 0.1,8 mm, score the actual grain - 7, cold sludge wire with a diameter of 21 mm by 68%, the temporary strength of 610 MPa, an elongation of 19%, narrowing 61%.

Ratio

C=0,32%, Mn=0,50%

Sa=0,0011%, S=0,008%

The introduction of the proposed product with stowage rental, round, medium-high-ductility steel - provides obtaining directly into the mill stream (without additional spheroidizing annealing) patterns of rolled. ensuring rational conditions of cold massive forming geometrically-complex high-strength fasteners.

SOURCES of INFORMATION

1. EN 2177510 C2 21 D 8/06, 27.12.2001.

2. SU 1703709, With 22 38/54, 07.01.1992.

3. SU 1772208 from 30.10.1992, bull. No. 40. With 22 38/12 (prototype).

Rolled, round, made of medium-carbon steel containing carbon and alloying elements that have the specified quality parameters become non-metallic inclusions, structure, mechanical properties, proclaimest deformation and technology of plasticity, characterized in that the steel contains the following ratio of components, wt.%:

Carbon 0,27-0,32

Manganese between 0.30 to 0.65

The silicon of 0.01-0,37

Chrome 0,01-0,25

Sera of 0,005 0,020

Niobium 0,005-0,02

Calcium 0,001-0,010

Iron and inevitable impurities Else

when performing ratios 12/S - MP/0,03≥20, Ca/S≥0,065 maximum score of contamination of steel, non-metallic inclusions in sulfides, oxides, silicates and nitrides of not greater than 3 points for each type of inclusions, car has a homogeneous spheroidizing structure p is the length, consisting of not less than 80% granular perlite, the amount of the actual grain 5-10 points, diameter from 10 to 30 mm, de-carbonized layer is not more than 1.5% of the diameter, the amount of cold upsetting of not less than 1/3 of the height, ultimate strength of not more than 620 MPa, elongation not less than 18%, the relative narrowing of not less than 55%.



 

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FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from low-carbon steel composed of, wt %: carbon 0.17-0.25, manganese 0.30-0.65, silicon 0.01-0.17, sulfur 0.005-0.020, vanadium 0.005-0.07, niobium 0.005-0.02, calcium 0.001-0.010, iron and unavoidable impurities - the balance. When following relationships are fulfilled: 12/C-Mn/0.02 ≥ 27; 0.46 ≥ 6V+8Nb ≥ 0.22; Ca/S ≥ 0.065, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 80% grainy perlite; effective grain size 5-10 points; diameter 10-25 mm; carbon-free layer not exceeding 1.5% of diameter; cold setting value at least 1/3 height; point of maximum load not higher than 550 MPa; relative elongation at least 20%; and relative contraction at least 60%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously ensured improved characteristics of in-process plasticity and low level of stray hardening.

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from alloyed steel composed of, wt %: carbon 0.06-0.11, manganese 0.30-0.9, silicon 0.001-0.15, boron 0.0005-0.0050, vanadium 0.005-0.08, aluminum 0.02-0.06, titanium 0.01-0.04, sulfur 0.005-0.020, nitrogen 0.005-0.015, calcium 0.001-0.010, iron and unavoidable impurities - the balance. When following relationships are fulfilled: Ti/48+Al/27-N/14 ≥ 0.6 x 10-3; Mn+5.0C ≥ 0.80; Ca/S ≥ 0.065, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 60% grainy perlite; effective grain size 5-10 points; diameter 10-16 mm; carbon-free layer not exceeding 1.0% of diameter; cold setting value at least 1/3 height; throughout hardenability in circles up to 16 mm in diameter; point of maximum load not higher than 500 MPa; relative elongation at least 22%; and relative contraction at least 70%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously improved steel hardenability characteristics.

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from alloyed steel composed of, wt %: carbon 0.28-0.35, manganese 0.90-1.40, silicon 0.001-0.37, sulfur 0.005-0.020, chromium 0.001-0.35, vanadium 0.001-0.07, molybdenum 0.001-0.10, nickel 0.001-0.10, niobium 0.005-0.02, titanium 0.01-0.04, boron 0.0005-0.0050, aluminum 0.02-0.06, nitrogen 0.005-0.015, iron and unavoidable impurities - the balance. When following relationships are fulfilled: 12/C-Mn/0.055 ≤ 2.0; 500(Ti/24-N/7)+0.2 ≥ 0; 40 ≥ C/0.01+B/0.001 ≥ 0.33, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 80% perlite; effective grain size 5-10 points; diameter of wire 10-25 mm; carbon-free layer not exceeding 1.5% diameter; cold setting value at least 1/3 height; throughout hardenability in circles up to 23 mm in diameter; point of maximum load not higher than 640 MPa; relative elongation at least 18%; and relative contraction at least 55%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously improved steel hardenability characteristics.

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from steel containing carbon and alloying elements, having specified parameters of metallurgical quality, structure, mechanical properties, hardenability, and in-process plasticity and characterized by being composed of, wt %: carbon 0.17-0.25, manganese 0.90-1.40, silicon 0.01-0.17, sulfur 0.005-0.020, chromium 0.001-0.35, vanadium 0.001-0.07, nickel 0.001-0.10, copper 0.001-0.10, molybdenum 0.001-0.10, titanium 0.01-0.04, boron 0.0005-0.0050, calcium 0.001-0.010, iron and unavoidable impurities - the balance. When following relationships are fulfilled: 22 ≤ 12/C-Mn/0.055 ≤ 47Ni/10Ti+Al ≤ 0.039; 10B-0.01C/N ≥ 1.80, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 80% perlite; effective grain size 5-10 points; diameter of wire 10-25 mm; carbon-free layer not exceeding 1.5% diameter; cold setting value at least 1/3 height; throughout (90%) hardenability in circles up to 19 mm in diameter; point of maximum load not higher than 580 MPa; relative elongation at least 18%; and relative contraction at least 60%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously improved steel hardenability characteristics.

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from steel containing, wt %: carbon 0.10-0.15, manganese 0.90-1.40, silicon 0.001-0.37, sulfur 0.005-0.020, chromium 0.001-0.35, nickel 0.005-0.10, niobium 0,005-0.02, titanium 0.01-0.04, boron 0.0005-0.0050, aluminum 0.02-0.06, nitrogen 0.005-0.015, iron and unavoidable impurities - the balance. When following relationships are fulfilled: 500(Ti/24-N/7)+0.2 ≥ 0; 40 ≥ C/0.01+B/0.0001 ≥ 3.0, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 80% perlite; effective grain size 5-10 points; diameter of wire 10-23 mm; carbon-free layer not exceeding 2.5% diameter; cold setting value at least 1/3 height; throughout hardenability in circles up to 15 mm in diameter; point of maximum load not higher than 520 MPa; relative elongation at least 20%; and relative contraction at least 65%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously improved steel hardenability characteristics.

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

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 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

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

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from steel containing, wt %: carbon 0.10-0.15, manganese 0.90-1.40, silicon 0.001-0.37, sulfur 0.005-0.020, chromium 0.001-0.35, nickel 0.005-0.10, niobium 0,005-0.02, titanium 0.01-0.04, boron 0.0005-0.0050, aluminum 0.02-0.06, nitrogen 0.005-0.015, iron and unavoidable impurities - the balance. When following relationships are fulfilled: 500(Ti/24-N/7)+0.2 ≥ 0; 40 ≥ C/0.01+B/0.0001 ≥ 3.0, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 80% perlite; effective grain size 5-10 points; diameter of wire 10-23 mm; carbon-free layer not exceeding 2.5% diameter; cold setting value at least 1/3 height; throughout hardenability in circles up to 15 mm in diameter; point of maximum load not higher than 520 MPa; relative elongation at least 20%; and relative contraction at least 65%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously improved steel hardenability characteristics.

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from steel containing carbon and alloying elements, having specified parameters of metallurgical quality, structure, mechanical properties, hardenability, and in-process plasticity and characterized by being composed of, wt %: carbon 0.17-0.25, manganese 0.90-1.40, silicon 0.01-0.17, sulfur 0.005-0.020, chromium 0.001-0.35, vanadium 0.001-0.07, nickel 0.001-0.10, copper 0.001-0.10, molybdenum 0.001-0.10, titanium 0.01-0.04, boron 0.0005-0.0050, calcium 0.001-0.010, iron and unavoidable impurities - the balance. When following relationships are fulfilled: 22 ≤ 12/C-Mn/0.055 ≤ 47Ni/10Ti+Al ≤ 0.039; 10B-0.01C/N ≥ 1.80, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 80% perlite; effective grain size 5-10 points; diameter of wire 10-25 mm; carbon-free layer not exceeding 1.5% diameter; cold setting value at least 1/3 height; throughout (90%) hardenability in circles up to 19 mm in diameter; point of maximum load not higher than 580 MPa; relative elongation at least 18%; and relative contraction at least 60%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously improved steel hardenability characteristics.

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from alloyed steel composed of, wt %: carbon 0.28-0.35, manganese 0.90-1.40, silicon 0.001-0.37, sulfur 0.005-0.020, chromium 0.001-0.35, vanadium 0.001-0.07, molybdenum 0.001-0.10, nickel 0.001-0.10, niobium 0.005-0.02, titanium 0.01-0.04, boron 0.0005-0.0050, aluminum 0.02-0.06, nitrogen 0.005-0.015, iron and unavoidable impurities - the balance. When following relationships are fulfilled: 12/C-Mn/0.055 ≤ 2.0; 500(Ti/24-N/7)+0.2 ≥ 0; 40 ≥ C/0.01+B/0.001 ≥ 0.33, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 80% perlite; effective grain size 5-10 points; diameter of wire 10-25 mm; carbon-free layer not exceeding 1.5% diameter; cold setting value at least 1/3 height; throughout hardenability in circles up to 23 mm in diameter; point of maximum load not higher than 640 MPa; relative elongation at least 18%; and relative contraction at least 55%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously improved steel hardenability characteristics.

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from alloyed steel composed of, wt %: carbon 0.06-0.11, manganese 0.30-0.9, silicon 0.001-0.15, boron 0.0005-0.0050, vanadium 0.005-0.08, aluminum 0.02-0.06, titanium 0.01-0.04, sulfur 0.005-0.020, nitrogen 0.005-0.015, calcium 0.001-0.010, iron and unavoidable impurities - the balance. When following relationships are fulfilled: Ti/48+Al/27-N/14 ≥ 0.6 x 10-3; Mn+5.0C ≥ 0.80; Ca/S ≥ 0.065, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 60% grainy perlite; effective grain size 5-10 points; diameter 10-16 mm; carbon-free layer not exceeding 1.0% of diameter; cold setting value at least 1/3 height; throughout hardenability in circles up to 16 mm in diameter; point of maximum load not higher than 500 MPa; relative elongation at least 22%; and relative contraction at least 70%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously improved steel hardenability characteristics.

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