According to the shape, Shanghai Yanjiang International Trade Co., Ltd. can be divided into four categories: profiles, plates, pipes and metal products. In order to facilitate procurement, ordering and management, China currently divides steel into sixteen varieties:
category | Variety | Description |
Profile | Heavy rail | Rails with a weight of more than 30 kg per meter (including crane rails) |
Light Rail | Rails with a weight of less than or equal to 30 kg per meter | |
Large section steel | Ordinary steel round bar, square steel, flat steel, hexagonal steel, I-beam, channel steel, equilateral and unequal angle steel and rebar. Divided into large, medium and small by size. | |
Medium steel | ||
Small section steel | ||
Wire | Round steel and wire rods 5-10 mm in diameter | |
Cold-formed steel | Profiled steel formed by cold bending of steel or steel strip | |
High quality profiles | High quality steel round bar, square steel, flat steel, hexagonal steel, etc. | |
Other steel | Including heavy rail accessories, axle blanks, tires, etc. | |
Plate | Sheet steel | Steel plate with thickness equal to or less than 4 mm |
Thick steel plate | Steel plates with a thickness greater than 4 mm. Can be divided into middle plate (thickness greater than 4mm less than 20mm), thick plate (thickness greater than 20mm less than 60mm), extra thick plate (thickness greater than 60mm) | |
Steel strip | Also called strip steel, actually a long, narrow and rolled sheet of steel | |
Electrician silicon steel sheet | Also called silicon steel sheet or silicon steel sheet | |
Pipe | Seamless steel pipe | Jointless steel pipe produced by hot rolling, hot rolling, cold drawing or extrusion |
Welded steel pipe | A steel pipe or a steel strip is formed by crimping and then welded | |
metal products | metal products | Including steel wire, steel wire rope, steel wire, etc. |
First, the classification of profiles
1. Simple section steel
1 square steel - hot rolled square steel, cold drawn square steel; 2 round steel - hot rolled round steel, forged round steel, cold drawn round steel
3 wire; 4 flat steel; 5 spring flat steel; 6 angle steel - equal angle steel, unequal angle steel; 7 triangular steel
8 hexagonal steel; 9 bow steel; 10 elliptical steel
2. Complex section steel
1 I-beam - ordinary I-beam, light I-beam; 2 channel steel - hot-rolled channel steel (common channel steel, light channel steel), curved channel steel;
3H steel (also known as wide-legged I-beam); 4 steel rails - heavy rail, light rail, crane rail, other special rails; 5 window frame steel
6 steel sheet pile; 7 curved steel - cold-formed steel, hot-formed steel; 8 other
Second, the division of large, medium and small steel sections
Large | Medium | Small | |
I-beam | High ≥180mm | High <180mm | |
Channel steel | High ≥180mm | High <180mm | |
Equal angle steel | Side width ≥160mm | Side width 50-140mm | Side width 20-45mm |
Unequal angle steel | Side width ≥160×100mm | Side width 140×90-50×32 mm | Side width ≤ 45 × 28 mm |
Round steel | Diameter ≥90mm | 38-80mm in diameter | Diameter 10-36 mm |
Square steel | Side width ≥90mm | Side width 50-75 mm | Side width 10-25 mm |
flat steel | Width ≥120mm | 60-100 mm wide | Width 12-55 mm |
Rebar | Diameter ≥ 40 mm | Diameter 10-36 mm | |
Rivet steel | 10-22 mm in diameter | ||
other | Shaped steel: track shoes, steel sheet piles, etc. | Shaped steel, composite flat steel for small farm implements, etc. | Shaped steel, agricultural steel, window frame steel, etc. |
Third, hot rolled ribbed steel
1. Variety specification
The grade of hot-rolled ribbed bars consists of the minimum yield point of the HRB and the grade. H, R, and B are the first letters of the English word for hot rolled, ribbed, and bar. Hot-rolled ribbed steel bars are divided into three grades: HRB335 (old grade 20MnSi), HRB400 (old grade 20MnSiV, 20MnSiNb, 20MnTi) and HRB500.
2. Vanadium-containing grade III rebar
1 Vanadium-containing III grade threaded steel market has broad prospects. Vanadium-containing new grade III threaded steel bars (20MnSiV, 400Mpa) are alloyed with vanadium, niobium and titanium in the production process. Compared with ordinary grade II threaded steel bars, they have high strength and toughness. Good, good welding performance and good seismic performance. In the construction market in developed countries such as Europe, Grade III threaded steel accounts for 80% of the total rebar. For example, the United Kingdom, Germany, Australia, Japan and other countries have used high-strength vanadium-containing grade III threaded steel bars to reach 80-90%. In 1995, the former Ministry of Metallurgy and the Ministry of Construction jointly issued a document to promote the application. The Ministry of Construction incorporated the new III grade reinforced bar technical conditions into the national standard GBJ10-89 "Concrete Structure Design Code", which will be implemented as of January 1, 1997. Grade III rebar has been successfully applied in high-rise buildings, large power stations, bridges, tunnels, airports and other engineering projects, and has a broad market prospect. The Ministry of Construction requires that the amount of new grade III steel bars in 2002 should reach 50% of the total amount of rebar, and reach 80% at the end of the 10th Five-Year Plan. However, due to insufficient promotion and promotion, the usage is still much lower than that of the old Class II 335Mpa ordinary grade reinforced bar. Therefore, it is necessary to vigorously promote and promote the new Class III reinforced bar.
2 Advantages of vanadium-containing grade III threaded steel bars
A. Economy: Due to the high strength, the use of new grade III threaded steel bars can save 10-15% of steel compared to grade II threaded steel bars, thus reducing the construction cost of construction projects.
B, high strength, good toughness: using microalloying treatment, the yield point is above 400Mpa, the tensile strength is above 570Mpa, which is 20% higher than that of the second grade.
C. Anti-seismic: Vanadium-containing steel bars have high bending resistance, aging performance, high low cycle fatigue performance, and their seismic performance is significantly better than Grade II rebar.
D. Easy to weld: Since the carbon content is ≤0.54%, the welding performance is good, and it is suitable for various welding methods, and the process is simple and convenient.
E. Convenient construction: The new grade III threaded steel bar is used to increase the construction clearance, which provides a guarantee for construction convenience and construction quality.
Fourth, hot rolled H-beam
1. A method of expressing hot rolled H-beams.
H-beams are classified into three types: wide flange H-beam (HK), narrow flange H-beam (HZ) and H-beam (HU). The method is expressed as: height H × width B × web thickness t1 × wing thickness t2, such as H-shaped steel Q235, SS400 200 × 200 × 8 × 12 expressed as high 200mm wide 200mm web thickness 8mm, wing thickness 12mm Wide flange H-beam with grades Q235 or SS400.
2. Advantages of hot rolled H-beams H-beams are a new type of economical construction steel.
The section shape of H-shaped steel is economical and reasonable, and the mechanical properties are good. The points on the section during rolling are more uniform and the internal stress is small. Compared with ordinary I-beam, it has the advantages of large section modulus, light weight and metal saving. The structure is reduced by 30-40%; and because the inside and outside of the leg are parallel, the leg ends are right angles, and assembled into components, which can save welding and riveting work up to 25%. It is often used in large buildings (such as workshops, high-rise buildings, etc.) that require large interception capacity and good cross-section stability, as well as bridges, ships, lifting and transport machinery, equipment foundations, supports, foundation piles, etc.
Five, cold-formed steel
Cold-formed steel is an economical thin-section thin-walled steel, also known as steel-refrigerated curved or cold-formed profiles. It is a section steel of various cross-sectional shapes made by hot-rolling or cold-rolled strip as a blank. Cold-formed steel has the following characteristics:
1. The section is economical and reasonable, saving materials. The cross-sectional shape of the cold-formed steel can be designed according to needs, the structure is reasonable, and the section coefficient per unit weight is higher than that of the hot-rolled steel. Under the same load, the weight of the component can be reduced and the material can be saved. Cold-formed steel is used in building structures to save 38-50% of metal compared to hot-rolled steel, and can save 15-60% of metal for agricultural machinery and vehicles. Convenient construction and reduce overall costs.
2. With a wide variety of products, it is possible to produce various profiles with uniform wall thickness and complicated cross-section shape and cold-formed steel of various materials which are difficult to produce by the general hot rolling method.
3. The surface of the product is smooth, the appearance is good, the size is accurate, and the length can also be flexibly adjusted according to the needs, all of which are supplied according to the fixed length or multiple feet to improve the utilization rate of the material.
4. In production, it can also be combined with punching and other processes to meet different needs.
There are many kinds of cold-formed steels, which are divided into cross-sectional shapes, open, semi-closed and closed. The main products are cold-formed channel steel, angle steel, Z-shaped steel, cold-formed corrugated steel plate, square tube, rectangular tube, welded special-shaped steel tube and rolling door. Wait. The cold-formed steel that is usually produced has a thickness of 6 mm or less and a width of 500 mm or less. Products are widely used in mining, construction, agricultural machinery, transportation, bridges, petrochemical, light industry, electronics and other industries.
First, the length of the steel
The length of the steel is the most basic size of various steels. It refers to the length, width, height, diameter, radius, inner diameter, outer diameter and wall thickness of the steel. The legal unit of measurement for the length of steel is meters (m), centimeters (cm), millimeters (mm). In current practice, it is also expressed in inches ("), but it is not a legal unit of measure.
1. The range of steel is fixed
It is an effective measure to save materials. The range is defined as the length or length, width, width, and not less than a certain size, or the length, length, width, and size of the delivery. Production units can supply and supply according to this size requirement.
2. Undetermined ruler (usual length)
Where the product size (length or width) is within the standard range, and does not require a fixed size, the indefinite size. The length of the indefinite length is also called the normal length (passing ruler). Metal materials delivered in indefinite lengths can be delivered within the specified length. For example, ordinary round steel of not more than 25 mm, the normal length of which is specified to be 4-10 m, the round steel having a length within this range can be delivered.
3. Fixed length
Cutting to a fixed size according to the order requirements is called a fixed length. When delivered in fixed lengths, the metal material must be of the length specified by the purchaser in the order contract. For example, if the contract states that the delivery is 5m in length, the materials delivered must be 5m long, and less than 5m or longer than 5m are unqualified. However, in fact, the delivery cannot be 5m long, so it is stipulated that a positive deviation is allowed, and a negative deviation is not allowed.
4. Double feet
It is called a multiple ruler that is cut into multiples according to the fixed size required by the order. When delivered in multiple lengths, the length of the metal material to be delivered must be an integral multiple of the length (called a single ruler) specified by the purchaser in the order contract (plus a kerf). For example, if the buyer wants the single-length ruler to have a length of 2m in the order contract, then the length is 4m when cut into double-doubles, and 6m when cut into three-fold rulers, and one or two saws are added respectively. . The amount of sawing is specified in the standard. When multiple measures are delivered, only positive deviations are allowed, and negative offset values ​​are not allowed.
Short rule
The length is less than the lower limit of the indeterminate length specified by the standard, but not less than the shortest length allowed. For example, water and gas transmission steel pipe standards stipulate that 10% (by number of roots) short-strip steel pipes of 2-4 m length are allowed per batch. 4m is the lower limit of the length of the indefinite length, and the shortest length allowed is 2m.
6. Narrow gauge
The width is less than the lower limit of the indeterminate width specified by the standard, but not less than the narrowest width allowed.
When delivering in narrow gauges, attention must be paid to the narrow and narrow gauges specified in the standard.
Second, the steel length size example
1. Length dimension of steel
(1) The standard length of train tracks is 12.5m and 25m.
(2) The dimensions of round steel, wire and steel wire are calibrated by the number of millimeters (mm) of diameter d.
(3) The square steel size is calibrated by the number of millimeters (mm) of the side length a.
(4) The size of hexagonal steel and octagonal steel is calibrated by the number of millimeters (mm) of the opposite side distance s.
(5) The size of the flat steel is calibrated by the width b and the number of millimeters (mm) of the thickness d.
(6) The dimensions of the I-beam and channel steel are calibrated by the waist height h, the leg width b, and the millimeter (mm) of the waist thickness d.
(7) The size of the equilateral angle steel is calibrated by the number of millimeters (mm) equal to the side width b and the side thickness d. The size of the unequal angle steel is calibrated by the number of millimeters (mm) of the side widths B, b and the side thickness d.
(8) The size of the H-section steel is calibrated by the web height h, the wing width b, the web thickness t1, and the millimeter (mm) of the blade thickness t2.
2. Length dimensions of steel plates and steel strips
(1) Generally, it is calibrated by the number of millimeters (mm) of the thickness d of the steel sheet. The steel strip is calibrated by the width b of the steel strip and the number of millimeters (mm) of the thickness d.
(2) The single steel plate has different sizes as specified. For example, the hot rolled steel plate has: 1 mm thick steel plate with a width of 600 × length 2000 mm; 650 × 2000 mm; 700 × 1420 mm;
750 × 1500 mm; 900 × 1800 mm; 1000 × 2000 mm.
3. Length of steel pipe
(1) Generally, the outer diameter D of the steel pipe, the inner diameter, and the millimeter (mm) of the wall thickness S are calibrated.
(2) Each type of steel pipe has different sizes, such as 50mm outer diameter of seamless steel pipe, 15 kinds of wall thickness of 2.5-10mm; or the same wall thickness of 5mm, outer diameter is 32-
29 species of 195mm. Another example is a welded steel pipe with a nominal diameter of 25 mm and a 3.25 mm ordinary steel pipe and a 4 mm thick steel pipe.
Third, the steel weight
The theoretical weight of steel
The theoretical weight of a steel is the theoretical weight calculated from the nominal size and density of the steel (previously referred to as specific gravity). This is directly related to the length, cross-sectional area and dimensional tolerance of the steel. Due to the allowable deviation of the steel in the manufacturing process, the theoretical weight calculated by the formula has a certain discrepancy with the actual weight, so it is only used as a reference for estimation.
2. The actual weight of the steel
The actual weight of steel refers to the weight of steel obtained by actual weighing (overweight), which is called the actual weight. The actual weight is more accurate than the theoretical weight.
3. Calculation method of steel weight
(1) Gross weight is the symmetry of "net weight", which is the total weight of the steel itself and the packaging materials. The transportation company calculates the freight by gross weight. However, in the purchase and sale of steel, it is calculated on the basis of net weight.
(2) Net weight is the symmetry of "gross weight". The weight of the steel minus the weight of the packaging material, that is, the actual weight, is called the net weight. In the purchase and sale of steel, it is generally calculated on the basis of net weight.
(3) The weight of the tare steel packaging material is called tare weight.
(4) Weight ton The weight unit used to calculate the freight rate based on the gross weight of the steel. Its legal unit of measurement is tons (1000kg), as well as long tons (inch weight unit 1016.16kg), short tons
(US weight unit 907.18kg).
(5) The billable weight is also known as “billing tons†or “freight tonsâ€. The transportation department collects the weight of the steel for the freight. Different transportation methods have different calculation standards and methods. For example, the whole vehicle is transported by rail, and the truck load weight is generally used as the billable weight. Road transport is combined with the carrier's deadweight tonnage to collect freight. For railways and highways, the gross weight of a few kilograms of gross weight is the minimum billable weight.
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