1. Steel length dimension
The length of steel is the most basic size of various steels, which refers to the length, width, height, diameter, radius, inner diameter, outer diameter and wall thickness of the steel. Statutory calculation of steel length
The unit of measurement is meter (m), centimeter (cm), millimeter (mm). In current practice, it is also expressed in inches (“), but it is not a legal unit of measurement.
1. The scope of steel
It is an effective measure to save materials. Scope fixed-length means that the length or length multiplied by the width is not less than a certain size, or the length, length multiplied by the width from how many sizes to deliver the goods.
The production unit can produce and supply according to this size requirement.
2. Variable length (usual length)
Any product size (length or width) that is within the range specified by the standard and does not require a fixed size is called an indefinite rule. Indefinite length is also called normal length (through ruler). Indefinite
The metal materials delivered by the ruler only need to be delivered within the specified length. For example, ordinary round steel not larger than 25mm, its usual length is specified as 4-10m, then the length is within this range
Round steel can be delivered.
3. Fixed length
Cut to a fixed size according to the order requirements is called fixed-length. When delivering according to the fixed-length length, the metal material must have the length specified by the purchaser in the order contract. For example, betting on the contract
It is stated that if the delivery is made according to a fixed-length length of 5m, the delivered materials must be 5m long. Anything shorter than 5m or longer than 5m is not qualified. But in fact, delivery cannot be 5m long, so it is stipulated
Positive deviation is allowed, but negative deviation is not allowed.
4. Times
The fixed size cut into integral multiples according to the order requirements is called a double ruler. When delivering in multiple lengths, the length of the metal material must be the length specified by the purchaser in the order contract
(Called single ruler) integer multiples (plus saw cut). For example, if the buyer requires a single ruler length of 2m in the order contract, then the length of the double ruler is 4m when cut into
When 3 times the ruler is 6m, add one or two cuts respectively. The amount of saw cut is specified in the standard. When the double ruler is delivered, only positive deviation is allowed, and negative deviation is not allowed.
5. Short feet
The length is less than the lower limit of the indefinite length specified by the standard, but not less than the shortest allowed length is called short ruler. For example, the water and gas transportation steel pipe standard stipulates that each batch has
10% (calculated by the number) of short steel pipes with a length of 2-4m. 4m is the lower limit of indefinite length, and the shortest allowed length is 2m.
6. Narrow ruler
The width is less than the lower limit of the indefinite width specified by the standard, but not less than the narrowest width allowed is called narrow rule.
When delivering the goods according to the narrow rule, you must pay attention to the narrow rule ratio and the narrowest rule stipulated by the relevant standards.
2. Examples of steel length dimensions
1. Length dimension of section steel
⑴ There are two standard lengths of train tracks: 12.5m and 25m.
⑵The dimensions of round steel, wire and steel wire are calibrated in millimeters (mm) of diameter d.
⑶ The size of square steel is calibrated in millimeters (mm) of side length a.
⑷The size of hexagonal steel and octagonal steel is calibrated by the number of millimeters (mm) of the distance s from opposite sides.
⑸The size of flat steel is calibrated in millimeters (mm) of width b and thickness d.
⑹The dimensions of I-beam and channel steel are calibrated in millimeters (mm) of waist height h, leg width b and waist thickness d.
⑺ The size of equilateral angle steel is calibrated in millimeters (mm) of equal side width b and side thickness d. The size of unequal angle steel is calibrated in millimeters (mm) of side width B, b and side thickness d.
⑻The size of H-shaped steel is calibrated in millimeters (mm) of web height h, wing plate width b, web thickness t1, and wing plate thickness t2.
2. Length dimension of steel plate and steel belt
⑴ Generally calibrated by the number of millimeters (mm) of the thickness d of the steel plate. The steel strip is calibrated in millimeters (mm) of the width b and thickness d of the steel strip.
⑵There are different sizes of single steel plates, such as hot-rolled steel plates: 1mm thick steel plate with width 600×length 2000 mm; 650×2000 mm; 700×1420 mm;
750×1500 mm; 900×1800 mm; 1000×2000 mm, etc.
3. Length of steel pipe
⑴ Generally calibrated by the number of millimeters (mm) of the outer diameter D, inner diameter and wall thickness S of the steel pipe.
⑵ Each kind of steel pipe has different sizes, such as seamless steel pipe with an outer diameter of 50mm and 15 kinds with a wall thickness of 2.5-10mm; or the same wall thickness of 5mm, with an outer diameter of 32-
29 kinds of 195mm. Another example is a welded steel pipe with a nominal diameter of 25mm and a wall thickness of 3.25mm with ordinary steel pipes and 4mm thick steel pipes.
3. Steel weight
1. Theoretical weight of steel
The theoretical weight of steel is calculated based on the nominal size and density of the steel (in the past called specific gravity) and called the theoretical weight. This is related to the length and cross-section of steel
There is a direct relationship between area and size tolerance. Due to the allowable deviation of steel in the manufacturing process, the theoretical weight calculated by the formula is different from the actual weight.
Take it only as a reference for estimation.
2. The actual weight of the steel
The actual weight of the steel refers to the weight obtained by the actual weighing (weighing) of the steel, which is called the actual weight. The actual weight is more accurate than the theoretical weight.
3. Calculation method of steel weight
⑴ Gross weight is the symmetry of “net weight”, which is the total weight of the steel itself and packaging materials. The transportation company calculates the freight based on gross weight. However, steel purchases and sales are calculated based on net weight.
⑵ Net weight is the symmetry of “gross weight”. The weight of the gross weight of the steel minus the weight of the packaging material, namely the actual weight, is called the net weight. In steel purchase and sale, it is generally calculated by net weight.
⑶ Tare weight The weight of steel packaging materials, called tare weight.
⑷ Weight ton The unit of weight used when calculating freight based on the gross weight of steel. Its legal unit of measurement is ton (1000kg), as well as long ton (1016.16kg in British system) and short ton
(US weight unit 907.18kg).
⑸ Billable weight, also known as “billing ton” or “freight ton”. The weight of the steel that the transportation department charges for freight. Different transportation methods have different calculation standards and methods. Such as railway
For vehicle transportation, the marked load of the truck is generally used as the chargeable weight. Road transportation is based on the tonnage of the vehicle to collect freight. LTL on railways and highways is based on gross weight
A few kilograms is the minimum chargeable weight, and it is rounded when it is insufficient.
4. Calculation of theoretical steel weight
The unit of measurement for calculating the theoretical weight of steel is kilogram (kg). The basic formula is:
W (weight, kg) = F (cross-sectional area mm2) × L (length, m) × ρ (density, g/cm3) × 1/1000
The density of steel is: 7.85g/cm3, the theoretical weight calculation formula of various steels is as follows:
Name (unit) Calculation formula Symbol meaning Calculation example
Round steel wire rod
(kg/m) W = 0.006165 × d × d d = round steel with diameter mm in diameter 100 mm, find the weight per m. Weight per m = 0.006165 ×1002=61.65kg
Rebar (kg/m) W= 0.00617 ×d×d d = cross-sectional diameter mm Rebar with a cross-sectional diameter of 12 mm, find the weight per m. Weight per m =0.00617 ×12 2=0.89kg
Square steel (kg/m) W= 0.00785 × a × a a = square steel with side width mm and side width 20 mm, find the weight per m. Weight per m = 0.00785 ×202=3.14kg
flat steel
(kg/m) W = 0.00785 × b × d b = side width mm
d = Flat steel with thickness mm, side width 40 mm and thickness 5mm, find the weight per m. Weight per m = 0.00785 ×40 ×5 = 1.57kg
Hexagonal steel
(kg/m) W= 0.006798 ×s×s s= distance between opposite sides mm Hexagonal steel with distance between opposite sides 50 mm, find the weight per m. Weight per m = 0.006798 ×502=17kg
Octagonal steel
(kg/m) W= 0.0065 ×s ×s s= distance between opposite sides mm octagonal steel with distance between opposite sides 80 mm, find the weight per m. Weight per m = 0.0065 ×802=41.62kg
Equilateral Angle Steel
(kg/m) = 0.00785 ×[d (2b – d) +0.215 (R2 – 2r 2)] b = side width
d = side thickness
R = inner arc radius
r= radius of end arc. Find the weight per m of 20 mm × 4mm equilateral angle steel. From the catalog of metallurgical products, it is found that the R of 4mm × 20 mm equilateral angle steel is 3.5 and r is 1.2, so the weight per m = 0.00785 × [4 × (2 × 20 – 4) +0.215 × (3.52 – 2 × 1.2 2 ) ]=1.15kg
Unequal angle steel
(kg/m) W = 0.00785 ×[d (B+b – d) +0.215 (R2 – 2 r 2)] B = long side width
b = short side width
d = side thickness
R = inner arc radius
r= radius of end arc. Find the weight per m of 30 mm × 20 mm × 4 mm unequal angle steel. From the catalog of metallurgical products, it is found that R of 30 × 20 × 4 unequal angle steel is 3.5 and r is 1.2, then the weight per m = 0.00785 × [4 × (30+20 – 4) +0.215 × (3.52 – 2 × 1.2 2) ]=1.46kg
Channel steel
(kg/m) W=0.00785 ×[hd+2t (b – d) +0.349 (R2 – r 2)] h = high
b = leg length
d = waist thickness
t = average leg thickness
R = inner arc radius
r= radius of end arc Find the weight per m of a channel steel of 80 mm × 43 mm × 5 mm. It is found from the metallurgical product catalog that the channel steel t is 8, R is 8, r is 4, then the weight per m = 0.00785 × [80 × 5 + 2 × 8 × (43 – 5) +0.349 × (82 – 4 2) ]=8.04kg
I-beam (kg/m) W = 0.00785 ×[hd+2t (b – d) +0.615 (R2 – r 2)] h = high
b = leg length
d = waist thickness
t = average leg thickness
R = inner arc radius
r= radius of end arc. Find the weight per m of I-beam of 250 mm ×118mm ×10mm. It is found from the metal material manual that the I-beam t is 13, R is 10, and r is 5, so the weight per m = 0.00785 × [250 × 10 + 2 × 13 × (118 –10) +0.615 × (102 – 5 2) ]=42.03kg
Steel plate (kg/m2) W= 7.85 × d d= thickness Steel plate with thickness of 4mm, find the weight per m2. Weight per m2 =7.85 ×4=31.4kg
Steel pipe (including no
Seam steel pipe and welding
Steel pipe (kg/m) W = 0.02466 ×S (D-S) D = outer diameter
S = wall thickness seamless steel pipe with an outer diameter of 60 mm and a wall thickness of 4 mm, find the weight per m. Weight per m = 0.02466 ×4 × (60 –4) =5.52kg