What is an Alloy Steel Hollow Bar?

An alloy steel hollow bar is a seamless tube with a thick wall. It is often used to make shafts or cylinders. We use alloy steel grades like 4140 and 4130 to make these bars because they have better mechanical properties than carbon steel. The hollow construction makes it lighter without compromising its strength. Manufacturers use hollow bars to reduce machining time when making components with central bores. The seamless construction eliminates weld seam concerns in rotating or high-stress applications. These products are also commonly referred to as seamless hollow bar, hollow shaft, and thick-wall seamless tube.

Alloy Steel Hollow Bars Grades Available

AISI 4140 Hollow Bar

4140 hollow bar is a chrome-moly alloy with good hardenability, strength, and toughness. This is our most popular grade for general-purpose applications. It responds well to heat treatment and machines efficiently in annealed condition.

AISI 4130 Hollow Bar

The 4130 hollow bar has lower carbon than 4140. This provides better weldability. Aircraft and motorsport industries prefer this grade where welding is required. The chrome-moly composition still provides good strength and fatigue resistance.

AISI 4340 Hollow Bar

The 4340 hollow bar is a nickel-chrome-moly alloy with the highest strength and toughness. Critical applications like aircraft landing gear and heavy-duty equipment use this grade. It handles severe stress and impact loads where other grades fall short.

EN19/42CrMo4 Hollow Bar

The EN19 hollow bar is the European equivalent to AISI 4140. Machinery builders specify this grade for shafts, spindles, and power transmission components. The proven performance in industrial applications makes EN19 a reliable choice.

Alloy Steel Hollow Bars Specifications

The following hollow bar specifications, like grades, dimensions, standards, etc., outline our product range.

Material Alloy Steel
Outer Diameter 10-100mm
Wall Thickness 2-20mm
Length 1-6m
Surface Finish Smooth
Standards ASTM A216
Usage Structural applications, mechanical components, hydraulic systems, and more
Features High Strength, Corrosion Resistant, Easy Installation, Durable, Precise Finish

Alloy Steel Hollow Bars Chemical Composition

Chemical composition determines the heat treatment response and mechanical properties of each grade.

Ni Fe Cr C Si Mn P S N
8 - 11 Balance 18 - 20 0.035 max 0.75 max 2 max 0.040 max 0.030 max 0.10 - 0.16

Alloy Steel Hollow Bars Mechanical Properties

Mechanical properties after heat treatment determine application suitability. Quenched and tempered condition provides the highest strength values.

Density 8.0 g/cm3
Melting Point 1400 °C (2550 °F)
Tensile Strength Psi - 75000 , MPa - 515
Yield Strength (0.2%Offset) Psi - 30000 , MPa - 205
Elongation 35 %

Applications

The alloy steel hollow bar is used in 3 major industrial applications:

Hydraulic Cylinders

Cylinder tubes and piston rods for hydraulic systems use alloy steel hollow bars. Construction equipment, industrial machinery, and mobile hydraulics require the strength and bore quality these bars provide. The seamless construction handles high hydraulic pressures safely.

Oil & Gas

Drill collars, stabilisers, and downhole tools demand high-strength hollow bars. The oil field environment requires materials that resist fatigue and withstand severe service conditions. Our grades meet the mechanical requirements for drilling operations.

Machinery Shafts

Drive shafts, spindles, and rotating equipment components benefit from hollow bar construction. The reduced weight improves efficiency while the thick wall handles torque and bending loads. Hollow shafts also allow passage of coolant, cables, or other components through the centre.