C20, C45, 1020, 1045, S355 Steel Round/Flat Bar

Nov 14, 2025

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Product Description

Surface Alloy Stainless Steel Hot Dipped Galvanized Round Bar

Surface Alloy Stainless Steel Hot Dipped Galvanized Round Bar

Surface Alloy Stainless Steel Hot Dipped Galvanized Round Bar

Surface Alloy Stainless Steel Hot Dipped Galvanized Round Bar

Surface Alloy Stainless Steel Hot Dipped Galvanized Round Bar

structural carbon steel :45# with details in under sheet :

Standard No. Alloy No. Chemical compositions(%)
C Cr Mn Ni P S Si
GB/T699-1999 45# 0.42~0.50 ≤0.25 0.50~0.80 ≤0.25 ≤0.035 ≤0.035 0.17~0.37
Mechanical
Property
Tensile Strength(Mpa) Yeild Strength(Mpa) Elongation(%) Contraction of area Z(%)
≥600 ≥355 ≥16 ≥40

The correlation between properties and parameters-S45C (JIS)-SAE1045(Aisi)-SM45 of No. 45 steel(45 steel) was studied:
No. 45 steel is a carbon structural steel with 0.45% carboncontent. It is characterized by low price, good cutting performance, high hardness after quenching, good strength, toughness and wear resistance after quenching and temperingtreatment, is widely used in manufacturing structural partsand low-grade plastic mold. "45 steel" is a popular name, thesymbol is generally recorded as"45 #". In fact GB standardsteel number is"45", it is not a sequential number, read as"45steel" is not very accurate. Ingredient code 45 steels of similar designation are S45C (JIS) and 1045(Aisi) . In addition, ourcountry metallurgical technology standard has SM45 brandnumber to express the plastic mold use specially. Comparedwith 45 steel, SM45 has lower phosphorus and sulfur contentand better steel purity.

Standards YB/T 094 AISI JIS G4051
Alloy No. SM45 1045 S45C
C 0.42-0.48 0.43-0.50 0.42-0.48
Si 0.17-0.37   0.15-0.35
Mn 0.50-0.80 0.60-0.90 0.60-0.90
P <0.030 <0.030 <0.030
S <0.035 <0.035 <0.035



Recommended process specification for heat treatment andhardness: quenching temperature 820 - 860" C, water-oroil-cooled, hardness 250 HRC. Recommended tempering pro-cess specifcation: tempering temperature is 500 - 560" C, aircooling, hardness is 25 - 33HRC. Tempering in this temperature range is the tempering treatment, Quenching and tempering make the strength, plasticity and toughness of 45 steelget a good balance, the comprehensive performance is good,can adapt to the alternating load environment. After quench-ing and tempering, the surface hardness of 45 steel is low anddoes not wear well. So commonly used quenching and tempering + surface quenching to improve the surface hardnessof parts.

Tempering temperature After quenching Unit centigrade
200 300 400 500 550 600
Hardness
HRC
57 55 50 41 33 26 22
Mechanical properties (GB/T 699-1999)
Sample size mm 25
Heat treatments recommended Normalizing ºC 850
Quenching ºC 840
Tempering ºC 600
Mechanical properties Tensile strongth Mpa ≥600
Strong yield Mpa ≥355
Elongation Mpa ≥16
Section shrinkago Mpa ≥40
Impact Mpa ≥39
Hardness of delivery   HB ≤229
  HB ≤197

Main Products

 

Surface Alloy Stainless Steel Hot Dipped Galvanized Round Bar

Surface Alloy Stainless Steel Hot Dipped Galvanized Round Bar

Surface Alloy Stainless Steel Hot Dipped Galvanized Round Bar

Surface Alloy Stainless Steel Hot Dipped Galvanized Round Bar

Surface Alloy Stainless Steel Hot Dipped Galvanized Round Bar

Surface Alloy Stainless Steel Hot Dipped Galvanized Round Bar

 

 

1.What is a round bar?

Round bar is a steel bar with a smooth surface which is used for construction that does not request high-strength reinforced concrete works. It is widely used on beam and column stirrups, pipelines, roads, small and medium-sized projects.

 

2.What is the difference between a round bar and a rod?

Round bars, made from steel or stainless steel alloys, have more carbon than rods. While this composition increases their strength, it also makes them prone to brittleness and cracks. Rods made from mild steel alloys with less carbon are less brittle and more flexible but not as strong as round bars.

 

3.Which is better, SS or MS?

Fabrication. As chrome is a hard alloy, stainless steels are much more impact resistant compared to mild steel and (although relatively easy to fabricate) are not as easy to fabricate as mild steel. Mild steel is much more malleable compared to stainless and so is used a lot in general fabrication.

 

4.What does a round bar look like?

Round Bar is a cylindrical metal bar with a circular cross-section. It is one of the most common and versatile forms of metal stock, used in various applications across different industries.

 

5.What is the difference between a round bar and a hex bar?

Round bars perform well in rotating applications and machining; hex bars provide superior grip and torque transmission, while square bars offer excellent structural stability and easy fabrication. Each shape serves separate industrial purposes across automotive, aerospace, pharmaceutical, and engineering sectors.