Steel products technique of production
1st, in carbon steel definition and steel five elements
Is called the steel including the carbon 2% following iron-carbum alloys.
In the carbon steel five elements are refer to the chemical composition the main constituent, namely C, Si, Mn, S, P (carbon, silicon, manganese, sulfur, phosphorus). Next will be will mix in the gas inevitably in the steel-making process, including O, H, N (oxygen, hydrogen, nitrogen). In addition, with the aluminum - silicon deaeration calm craft, includes Al inevitably in the molten steel, when Als (acid dissolves aluminum) ≥0. when 020%, but also has the refined grain function.
2nd, how is the steel and iron builds up?
The steel-making primary mission is presses builds up the aluminum the quality requirement, adjusts in the steel the carbon and the alloying element content to the prescribed limit, under and causes impurity and so on P, S, H, O, N content to drop to the permission to limit the quantity. The steel-making process materially is an oxidation process, in the furnace charge the surplus carbon is oxidized, burns the CO gas escape, after other oxidations, and so on Si, P, Mn enters in the slag. The S part enters in the clinker, the part produces SO2 to discharge. After the molten steel ingredient and the temperature achieves the technological requirement, then tapping. For except steel in surplus oxygen and adjustment chemical composition, may increase the deoxidizer and the ferroalloy or the alloying element.
3rd, converter steel-making synopsis
Molten iron which comes from the torpedo vehicle transport then after the desulphurization, keeps off processing and so on dregs pours into the converter to take the main furnace charge, adds separately 10% following scrap steel. Then, blows the oxygen combustion to the converter, in the molten iron excessive carbon is oxidized and emits the massive quantity of heats, when the probe head obtains achieves the predetermined low-carbon content, namely stops blowing the oxygen and the tapping. Generally must carry on the deaeration and the adjustment ingredient operation in the hot metal ladle; Then throws in the molten steel surface carbonizes the rice husk to prevent the molten steel to oxidize, then escorts to the continuous casting or the die casting work area. To requests the high aluminum to be possible to increase the bottom to blow the argon, the RH vacuum treated, dusting processing (to spurt the SI-CA powder and denatured lime) may reduce in the steel effectively the gas and the mixture, and has further carbon drop and falls the sulfur the function. After these stoves fining measure may also the final trimming ingredient, satisfy the high quality steel products the demand.
4th, preliminary crushing
The die casting steel ingot adopts the hot attire, to deliver the new craft hotly, enters the ingot pit heating, then forms by rolling preliminary crushing products continually and so on tube blank, unfinished piping, small squares semifinished product through the blooming mill and the billet rolling mill, after the head metal, cuts the tail, the surface cleaning, (flame descaling, polish) the high quality product must carry on to the preliminary crushing semifinished product skins qualified with the crack detection, after the examination, goes into storage. At present the blooming mill product has the preliminary crushing tube blank, rolling Fang Pi, the oxygen cylinder with the billet, the gear with the round unfinished piping, the railroad car uses the steel with the vehicle plate blank and the mold and so on. The preliminary crushing tube blank main supply hot rolling factory takes raw material; Rolling Fang Pichu outside the part supplies, mainly escorts to the high speed rod mill to make raw material. As a result of the continuous casting tube blank's sophistication, the preliminary crushing tube blank's demand to reduce greatly, therefore changed the above other products.
5th, hot tandem rolling
Make raw material with the continuous casting tube blank or the preliminary crushing tube blank, after step-type heating furnace heating, after high-pressured water scale removal, enters the roughing mill, the rough rolling material after the head metal, the tail, enters the finishing mill again, implements the computer control rolling, after the finish to size, crosses the laminar to cool (computer control rate of cooling) immediately and the coiler volume takes, becomes sends directly the volume. Sends directly the volume the head, the tail often to assume the tongue and the fish tail shape, thickness, the width precision is bad, is everlasting in the wave shape, the flanging, tower-shaped and so on flaws. Its volume heavy is heavy, the steel volume inside diameter is 760mm. (general tube making profession likes using.)Will send directly the volume after the head metal, cuts the tail, the cutting edge and the multi-while going along strightening, smooth and so on finishing line processing, then cuts the board or the heavy volume, namely becomes: Hot rolling products and so on steel plate, smooth hot-rolled steel volume, slitting belt. If hot rolling finishing volume after acid pickling elimination oxide skin and Tu Youhou namely becomes the hot rolling acid pickling board volume. This product has partial substitutes the cold rolled plate's trend, the moderate cost, the depth the user community affection. A Baoshan Steel Corporation new investment's hot rolling acid pickling line is being constructed intensely.
6th, cold tandem rolling
With the hot-rolled steel volume is raw material, after acid pickling elimination oxide skin carries on the cold tandem rolling, its end product to roll over the hard volume, because the continual cold-work causes the hammer-harden causes to roll over the hard volume the intensity, degree of hardness rise, to model the target to drop strongly, therefore the ramming performance will worsen, can only use in the simple deformation the components. Rolls over the hard volume to be possible to take the pot galvanize factory raw material, because the pot galvanize unit establishes has draws back the firing line. Rolls over the hard volume heavy in 6~13.5 tons, the steel volume inside diameter is 610mm generally.
Generally the cold company rolled plate, the volume should pass through the continuous annealing (the CAPL unit) or the portable cover furnace annealing eliminate the hammer-harden and the rolling stress, achieves the corresponding standing operating procedure the mechanical properties target.
The cold rolling steel plate's surface quality, the outward appearance, the size precision surpass the hot rolled plate, and its product thickness rolls over right thinly to 0.18mm about, therefore depth the user community favor. Carries on the product take the cold rooled steel volume as the foundation plate the intensive processing, becomes the high added value product. Like the electricity galvanization, pot galvanize, bear the fingerprint electricity galvanization, the color to spread the steel plate volume and the antivibration compound steel plate, the PVC membrana tectoria steel plate and so on, enables these products to have, the high corrosion resistance artisticly and so on good quality, obtained the widespread application. Cold rooled steel volume after the annealing must carry on the finishing, including the head metal, the tail, the cutting edge, rectifies even, smooth, the heavy volume, or the longitudinal shear board and so on. The cold rolling product widely applies in professions and so on automobile manufacture, electrical appliances product, meter switch, building, office furniture. After the steel plate bundles package's each package of weights is 3~5 tons. The smooth minute volume heavy is 3~10 tons/volumes generally. Steel volume inside diameter 610mm.
7th, steel mechanical properties
7.1 tension test
According to the standard preparation's pulling force test specimen, installs in tensile testing machine's cartridge, exerts the single axle slowly to the test specimen to the tension stress, is pulled up to until the test specimen the experiment to be called as the tension test.
7.1.1 intensities
The metallic material under the exogenic process, the resistance distorts ability which and breaks to be called the intensity. The intensity index includes: Limit of proportionality, limit of elasticity, yield strength, tensile strength and so on.
7.1.2 limits of proportionality
Exerts the pulling force to the metal, the metal existence tries with to distort the straight line proportion stage, but this stage's biggest ultimate load Pp dividing test specimen's original plan area is the limit of proportionality, indicated with Sigma P.
7.1.3 limit of elasticity
The metal has been had the exogenic process the distortion, after the external force removes, can completely restore the original shape, this kind of distortion is called the elastic deformation. The metal can maintain the elastic deformation the biggest stress is called the limit of elasticity, with σe expressed.
7.1.4 tensile strengths
When test specimen stretch, withstands the biggest load before the abruption to divide the original plan area obtained stress, is called as the tensile strength, with σb expressed. When the material receives when the external stress is bigger than its tensile strength, will have the break. Therefore σb is higher, then expressed that it can withstand a bigger external stress not to send in the break.
The overseas standard's structural steel often classifies according to the tensile strength, if SS400, 400 are the expression σb minimum value is the 400MPa ultra high-tensile steel refers to σb≥1373 the Mpa steel.
7.1.5 tensile ratios
The tensile ratio is the yield strength and the tensile strength ratio of (σS/σb). Submitting ratio is higher, then this material's intensity is higher, the tensile ratio value is lower, then the plasticity is better, the ramming forming is better. If flushes steel plate's tensile ratio value deeply for ≤0.65.
The spring steel serves generally in the limit of elasticity scope, load when does not allow to have the plastic deformation, therefore requests the spring steel after quenching, the tempering has as far as possible the high limit of elasticity and the tensile ratio value (σS/σb≥0.90) in addition the fatigue life and the tensile strength and the surface quality often has the very big correlation.
7.1.6 plasticity
The metallic material before the stress destroys may undergo the permanent deformation the performance to be called the plasticity. Plastic target usual elongation ratio and reduction of area expression. The elongation ratio and the reduction of area are higher, then the plasticity is better.
8th, resilience
With certain size and the shape test button, is attacked when in the stipulation type's impact test the load breaks off, in the test specimen chamfer place unit lateral section consumes the impact merit, is called the resilience by αk the expression.
At present commonly used 10×10×55mm, belt 2 mm deep V shape gap Xia attacks the test specimen, in the standard uses the impact merit directly (J joule value) AK, but uses αK the value. Because in unit area impact merit and not practical significance.
The impact merit transforms regarding inspection metallic material's under different temperature brittleness sensitively, but actual serves under the condition disastrous breaking accident, often concerns with the material impact merit and the service temperature. Therefore in the related standard stipulated frequently when some temperature the impact merit for how many, also stipulated that FATT (fracture area inversion temperature) must be lower than some temperature the engineering factor. So-called FATT, namely a group washes away after the different temperature's impact test specimen, to the impact rupture carries on the evaluation, when the brittle fracture accounts for the total area 50% corresponds temperature. As a result of the steel plate thickness's influence, to thickness ≤10mm steel plate, may obtain 3/4 light-sized impact test specimen (7.5×10×55mm) or 1/2 light-sized impact test specimen (5×10×55mm). But must certainly pay attention, under the same specification and the identical temperature's impact merit only then may mutually the comparison. Only then under standing operating procedure's condition, only then may according to the standard conversion method, convert the standard impact test specimen impact merit, again mutually comparison.
9th, hardness test
The metallic material resistance discharge head (hard steel ball either has 1200 circular cones or pyramid diamond discharge heads) the pressure falls superficial ability to be called degree of hardness. According to the testing method and applicable scope's difference, degree of hardness may divide into the Brinell hardness, Luo river degree of hardness, vickers hardness, the scleroscope hardness as well as the microhardness, high temperature degree of hardness and so on.
What the metallurgical product is commonly used is the Brinell hardness and Luo river degree of hardness.
10th, Baoshan Steel Corporation enterprise standard (Q/BQB)
In the Baoshan Steel Corporation business sign's steel grade may divide into three origins approximately: Namely from the Japanese JIS standard, the German DIN standard transplant and develops the development voluntarily the steel grade. Steel grade which transplants from the Japanese JIS standard, generally first place Chang Weis (Steel); Steel grade which transplants from the DIN standard, generally often begins by ST (in the Stahl German “steel”); The Baoshan Steel Corporation develops the development voluntarily the steel grade, generally first place often by Baoshan Steel Corporation's Pinyin first place B opening.
11th, the structure uses the hot tandem rolling, the cold tandem rolling steel plate and the steel belt
Structural steel generally according to intensity classification, in steel grade digit often on behalf of tensile strength minimum value. Because this kind of steel commonly used in manufacture structural element, therefore is called as for the structural steel. The structural steel strengthened mechanism favors in the carbon drop increases the manganese melting strengthening ferrite, the refinement pearlyte and increases the micro alloy the separation to strengthen, the precipitation strengthening and the fine crystal strengthens, guaranteed that while enhanced the intensity still maintained good strong, models the target and has both the good welding performance.
Anything is grips coldly, the heat grips
The cold rolling and hot rolling is two kind of different steel rolling technologies, as the name suggests, the cold rolling is carries on the steel in the normal temperature situation makes articles out of plaited bamboo, this kind of steel's degree of hardness is big. Hot rolling is the steel makes articles out of plaited bamboo in the high temperature situation
(1) hot rolling:
1st, thickness: 1.2mm-8/12mm (thickness is different, price different)
2nd, width: 1000mm/1250mm/1500mm (non-sign width must increase price generally)
3rd, trademark:
Domestic: (hard, including carbon high) Q235-Q215-Q195 (soft, contains carbon lowly)
Japan: SS400-SS330-SPHC (domestic applies mechanically generally)
Commonwealth of Independent States: 08KP--08YU (strong drawing, flushes deeply)
Germany: ST12- ST13- ST14 (strong drawing, flushes deeply)
Zhugang: ZJ330 and so on
4th, the volume is heavy: Is mainly 15 tons/volumes, also has requests 10 tons below/volumes. Must consider Kaiping machine load-bearing, the hoisting equipment load-bearing and so on questions.
5th, productivity:
Thickness is 0.9/1.2/1.5 only then Zhugang can produce
Thickness is the 1.5mm Handan Iron and Steel Group Co., Ltd., the Baoshan Steel Corporation can produce (the Handan Iron and Steel Group Co., Ltd. quality to be bad)
Thickness is 1.8mm this steel, Anshan Iron and Steel Company, Taiyuan Steel Works can produce
6th, product quality and price:
Commonwealth of Independent States: The quality is bad, the price to be low. the 08KP Manufacturer has Ukraine ILLCHY, the ZAPROSTAL steel mill, Thacker the Stan INSPAT steel mill (Ukraine's quality is worst, price is lowest).
the 08YU Manufacturer has Russia (well (MMK) Ma Gang the 08YU quality in 08KP)
Japan: The quality is good, the price high main Manufacturer is six big blast furnace factories: New date iron, Sumitomo, NKK, Kawasaki and so on.
South Korea: The quality is good, the price high main Manufacturer is POSCO (Pohang)
Taiwan: The quality is good, the price is high, main Manufacturer for the steel, Yelong.
South Africa: Quality good in Commonwealth of Independent States, is only inferior to the Japan and South Korea, the main Manufacturer is SODHNA.
1.5-2.0 (do not include 1.5, including 2.0) the domestic factory quality is bad, 2.0 above qualities may satisfy the operation requirements.
below 1.5 mainly needs to import, 1.8-2.95 use Commonwealth of Independent States many.
(2) cold rolling:
1st, thickness: 0.25mm-3.00mm (thickness is different, price different)
2nd, width: 1000mm/1250mm (non-sign width must increase price generally)
3rd, trademark:
Domestic: (hard, including carbon high) Q235-Q195 (soft, contains carbon lowly) (to be many with Q195)
Japan: SPCC-SD-SPCD-SD-SPCE-SD (domestic applies mechanically generally)
Commonwealth of Independent States: 08KP--08YU (strong drawing, flushes deeply)
Germany: ST12- ST13- ST14/ST16 (strong drawing, flushes deeply)
4th, use present situation
below 1.0mm mainly needs to import.
Japan: Is mainly below 0.6mm/0.7mm
Commonwealth of Independent States: Is mainly below 1.1mm
Domestic: Is mainly above 0.8mm - below 3.0mm
5th, product quality:
Japan and South Korea: The quality is best, like POSCO and so on
Domestic: Middle-grade, the Baoshan Steel Corporation is best, Anshan Iron and Steel Company, this steel, Panzhihua Iron and Steel Co., the Wuhan Steel Corporation next
Commonwealth of Independent States: The quality is worst.
Main Manufacturer with hot rolling.