St3 · 20 · 45 · a 10–200 · GOST 2591
Hot-rolled square bar
Square bar with a side of 10–200 mm in St3, 20 and 45 to GOST 2591; equivalents Q235B, 20#, 45#
St3 · 20 · 45 · 40Kh · Ø10–300 · GOST 2590
Hot-rolled round bar
Round bar Ø10–300 mm in St3, 20, 45 and 40Kh to GOST 2590; equivalents Q235B, 20#, 45#, 40Cr
- GOST 2590-2006
- GOST 535-2005
- GOST 1050-2013
- GOST 4543-2016
- GB/T 702-2017
- GB/T 700-2006
- GB/T 699-2015
- GB/T 3077-2015
- St3sp
- St3ps
- 20
- 45
- 40Kh
- Q235B
- 20#
- 45#
- 40Cr
Section
Key parameters
- Diameter
- 10–300 mm; per GOST 2590 — up to 270 mm, larger — by agreement with the mill
- Length
- fixed and random length, 6 and 12 m — to specification
- Rolling accuracy
- AO1, A1–A3, B1, V1–V5 per GOST 2590
- Steel grade
- St3sp, St3ps, 20, 45, 40Kh
- Delivery condition
- hot-rolled; normalized or annealed — to specification
- Surface
- untreated, with mill scale; turned — to specification
Sizes and weight
Pick a size in the table: each row has a quantity field in tonnes and an “Add to specification” button. Rows from several items go out as one request.
Calculate for your volume
The same formula as the table below: metres to tonnes and tonnes to metres.
—kg per metre
—total, t
—metres per tonne
Formula
| Ø, mm | Weight, kg/m | Metres per tonne | Add to specification |
|---|---|---|---|
| 10 | Weight, kg/m0.617 | Metres per tonne1 622 | Add to specification |
| 12 | Weight, kg/m0.888 | Metres per tonne1 126 | Add to specification |
| 14 | Weight, kg/m1.21 | Metres per tonne827.5 | Add to specification |
| 16 | Weight, kg/m1.58 | Metres per tonne633.6 | Add to specification |
| 20 | Weight, kg/m2.47 | Metres per tonne405.5 | Add to specification |
| 25 | Weight, kg/m3.85 | Metres per tonne259.5 | Add to specification |
| 32 | Weight, kg/m6.31 | Metres per tonne158.4 | Add to specification |
| 40 | Weight, kg/m9.86 | Metres per tonne101.4 | Add to specification |
| 50 | Weight, kg/m15.4 | Metres per tonne64.9 | Add to specification |
| 60 | Weight, kg/m22.2 | Metres per tonne45.1 | Add to specification |
| 80 | Weight, kg/m39.5 | Metres per tonne25.3 | Add to specification |
| 100 | Weight, kg/m61.7 | Metres per tonne16.2 | Add to specification |
| 120 | Weight, kg/m88.8 | Metres per tonne11.3 | Add to specification |
| 150 | Weight, kg/m138.7 | Metres per tonne7.21 | Add to specification |
| 200 | Weight, kg/m246.6 | Metres per tonne4.05 | Add to specification |
Round bar mass per metre is 0.006165·d², where d is the diameter in mm.
Theoretical weight at steel density 7.85 g/cm³. Actual batch weight is by scale and mill certificate.
Description
Round bar is a hot-rolled bar of circular cross-section, the basic stock for shafts, axles, pins, fasteners and members of steel structures. Dimensions and tolerances are set by GOST 2590-2006, at mills in China by GB/T 702-2017. GOST 2590 covers diameters of 5–270 mm; round bar above 270 mm is rolled by agreement with the mill. Rolling accuracy classes under GOST 2590 are extra-high AO1, high A1–A3, raised B1 and ordinary V1–V5; for subsequent machining ordinary accuracy V1 is usually sufficient, for cold finishing and precision fits the raised class is agreed.
Details
The grade is chosen by the purpose of the part. St3sp and St3ps to GOST 535 are for structural and non-critical parts, equivalent Q235B. Steels 20 and 45 to GOST 1050 are quality carbon steels: steel 20 goes for carburizing and welded assemblies, steel 45 for hardening and quench-and-temper treatment; equivalents 20# and 45#. 40Kh to GOST 4543 is a chromium alloy steel for shafts and gears after heat treatment, equivalent 40Cr. The mill rolls round bar from continuously cast billet; the delivery condition is hot-rolled, or normalised or annealed by specification.
During inspection at the mill the bureau measures the diameter with a micrometer in two perpendicular directions on bars from different bundles and compares the ovality with the tolerance of the chosen accuracy class, checks straightness and surface — free of cracks, laps and scabs. The heat number on the tag is checked against the mill test certificate (MTC) and the chemical composition in the specification; for steels 45 and 40Kh the as-delivered hardness is also read. The paint grade marking on the bar ends and the strapping of bundles are checked; the result is an inspection report with photographs before shipment.
Applications
- shafts, axles, pins and rods in machine building
- stock for bolts, studs and anchors
- ties, braces and embedded parts of steel structures
- repair and tool shops of enterprises
- stock for cold finishing and subsequent machining
Packing and shipment
Bundles strapped with steel band or wire rod at several points, mill tag with grade, heat, size and weight; large diameters are loaded individually with marking on the ends.
Grade equivalents
Equivalents are the nearest, not identical: the exact grade and standard are written into the contract.
| GOST | GB (China) | ASTM | EN | Note |
|---|---|---|---|---|
| St3sp | GB (China)Q235B | ASTMA36 | ENS235JR | NoteNearest equivalents: carbon, manganese and impact toughness limits differ between the standards. The specification fixes the GOST grade and the control values. |
| Steel 20 | GB (China)20# | ASTM1020 | ENC22E | NoteQuality carbon steel; the equivalents match in carbon content, impurity limits are checked against the certificate. |
| Steel 45 | GB (China)45# | ASTM1045 | ENC45E | NoteSteel for heat treatment; hardness and delivery condition are checked — hot-rolled, normalised or annealed. |
| 40Kh | GB (China)40Cr | ASTM5140 | EN41Cr4 | NoteChromium alloy steel; the equivalents are close in composition, chromium content is confirmed by the heat certificate. |
| 09G2S | GB (China)Q355B | ASTMA572 Gr. 50 | ENS355JR | NoteNearest equivalents by strength; 09G2S specifies impact toughness at minus 40 °C, the equivalents use other test temperatures. |
| St1kp | GB (China)Q195 | ASTM1008 | EN— | NoteWire rod for drawing and tying wire; the nearest equivalent by carbon content, there is no single EN grade for this class. |
| 08Kh18N10 | GB (China)06Cr19Ni10 | ASTM304 | EN1.4301 | NoteAustenitic chromium-nickel steel; nearest equivalents: chromium and nickel ranges differ between the standards, composition is confirmed by the heat certificate. |
| 12Kh18N10T | GB (China)06Cr18Ni11Ti | ASTM321 | EN1.4541 | NoteTitanium-stabilised; nearest equivalents: the upper carbon limit is 0.12 % for 12Kh18N10T and 0.08 % for 321 and 1.4541; titanium content is checked against the certificate. |
| 03Kh17N14M3 | GB (China)022Cr17Ni12Mo2 | ASTM316L | EN1.4404 | NoteMolybdenum-bearing, low-carbon; nearest equivalents: the lower nickel limit of 03Kh17N14M3 is higher than that of 316L, composition is confirmed by the heat certificate. |
Equivalents are the closest match, not identical: chemistry and tolerances differ between standards. The exact grade and standard are written into the contract.
The batch is checked against the order at the mill before shipment: sizes, markings, heat numbers on the certificate and tags, packing
Documents
What arrives with the steel
01
Mill test certificate (MTC)
Heat number, chemical composition, mechanical properties and standard for every heat in the batch.
02
Photo-documented inspection report
Measurements, markings, packing, weighing and bundle numbers, drawn up at the mill before shipment.
03
Specification and packing list
Items, sizes, quantities and mass by bundle: what the warehouse acceptance is checked against.
04
Certificate of origin
Confirms the mill and country of manufacture for customs clearance.
Related items
20 · 45 · 40Kh · S 10–75 · GOST 2879
Hexagonal steel bar
Hexagonal bar 10–75 mm across flats in steels 20, 45 and 40Kh to GOST 2879; equivalents 20#, 45#, 40Cr
304 · 321 · 316L · Ø10–200 · GOST 5949
Stainless round bar
Austenitic steel bar Ø10–200 mm: 08Kh18N10, 12Kh18N10T, 03Kh17N14M3 to GOST 5949; equivalents 304, 321, 316L
Buyer questions
How to read a mill test certificate (MTC) for long products
In the certificate the mill states the heat number, grade and standard, the chemical composition of the heat, the mechanical properties from test results, the size and weight of the batch. The heat number must match the tag on the bundle or coil — this is the first thing the bureau's inspector checks. If the mill rolled to GB, the bureau attaches to the certificate a table of GOST-to-GB grade correspondence and the control values from the specification.
How St3 differs from steels 20, 45 and 40Kh
St3 is an ordinary-quality steel to GOST 535: strength is specified, impurities are allowed within wider limits; it goes into structures and non-critical parts. Steels 20 and 45 are quality carbon steels to GOST 1050: impurities are limited more tightly, properties are set by carbon content, steel 45 is used for hardening and quench-and-temper treatment. 40Kh is a chromium alloy steel to GOST 4543 for shafts, axles and gears after heat treatment. The grade is chosen from the part drawing, not from what is in stock.
How the tonnage of long products is calculated
The theoretical weight per metre is calculated from the cross-sectional area and the steel density of 7.85 g/cm³: round bar 0.006165·d², square bar 0.00785·a², flat bar 0.00785·b·t in kilograms per metre with dimensions in millimetres. The specification and the contract with the mill are drawn up on theoretical weight. Shipment and acceptance at the warehouse go by actual weight from weighing; the difference from theory lies within the dimensional tolerances of the standard.
What the bureau checks when inspecting a batch at the mill
Cross-section — with a micrometer and a calliper in two perpendicular directions on bars from different bundles, checked against the GOST tolerances for the rolling accuracy class. Documents — the heat number on the tag against the certificate, the chemical composition against the specification, for stainless grades a rapid composition check with a portable spectrometer. Appearance — surface free of cracks, laps and scabs, straightness, twist of square and hexagonal bar. Packing — strapping of bundles, a legible tag, grade marking on the bar ends. Everything is recorded in an inspection report with photographs.
How a batch is sized and what to send for a quotation
The batch is sized to your volume — send your specification: steel grade to GOST, product type and cross-section size, rolling accuracy class, bar length or coil weight, volume in tonnes for each size, certificate and packing requirements. On the specification the bureau selects a mill, agrees terms with it and returns to you a draft contract describing inspection and acceptance.
Price request
Send your specification and we will quote your batch
Price depends on grade, size, tonnage and delivery terms on the day of contract.
Request received