Hot rolled 1045 carbon steel round bar is a widely used material in the machinery industry due to its balanced mechanical properties, cost-effectiveness, and versatility.

Chemical Composition of Hot Rolled 1045 Carbon Steel Round Bar for Machinery

Element	Chemical Symbol	Typical Content (Mass Fraction, %)
Carbon	C	0.42 - 0.48
Manganese	Mn	0.60 - 0.90
Phosphorus	P	≤ 0.040
Sulfur	S	≤ 0.040
Silicon	Si	0.15 - 0.35
Iron	Fe	Matrix
Other Elements	-	Total ≤ 0.50 (e.g., Cr, Ni, Cu)

What is the Tolerance ofour Round bar?

Tolerance OD mm	H7	H8	H9	H10	H11	F7	F8
6-10	0-0.015	0-0.022	0-0.036	0-0.058	0-0.09	-0.013-0.028	-0.013-0.035
10-18	0-0.018	0-0.027	0-0.043	0-0.058	0-0.09	-0.016-0.034	-0.016-0.043
18-30	0-0.021	0-0.033	0-0.052	0-0.084	0-0.13	-0.02-0.041	-0.02-0.053
30-50	0-0.025	0-0.039	0-0.062	0-0.1	0-0.16	-0.025-0.05	-0.025-0.064
50-80	0-0.030	0-0.046	0-0.074	0-0.12	0-0.19	-0.03-0.06	-0.03-0.076
80-120	0-0.035	0-0.054	0-0.087	0-0.14	0-0.22	-0.036-0.071	-0.036-0.9

Hot Rolled 1045 Carbon Steel Round Bar: Applications in Machinery Equipment

Application Category	Specific Applications	Key Reasons
Gear Manufacturing	Gears in gearboxes, transmissions, and drive systems for industrial presses, conveyors, agricultural equipment.	Offers high tensile strength (600–800 MPa) and hardness (up to 55 HRC after quenching and tempering), withstands heavy loads and wear. Good machinability enables precise gear cutting.
Shafts and Axles	Drive shafts, crankshafts, camshafts in engines; axles in construction and mining equipment.	Excellent toughness and fatigue resistance handle torsional forces and cyclic loading. Hot rolling enhances structural integrity, reducing fracture risk under dynamic stress.
Fasteners and Hardware	Bolts, nuts, studs for assembling industrial machinery frames, hydraulic systems, and heavy-duty components.	Heat-treatable to meet high-torque fastening strength requirements. Cost-effective for large-scale production.
Hydraulic and Pneumatic Components	Pistons, cylinder rods, valves in hydraulic pumps, cylinders, and pneumatic systems.	Combines strength with machinable surface finish for durability in fluid-powered systems. Resists wear from hydraulic fluids and mechanical abrasion.
Tooling and Fixtures	Jigs, fixtures, dies for machining operations; simple cutting tools (drills, taps) for low-volume/non-critical applications.	Locally hardenable (e.g., case hardening) to form wear-resistant surfaces while retaining a tough core, suitable for tooling needing strength and impact resistance.
Structural Components	Connecting rods, levers, supports in textile machines, printing presses, packaging equipment.	Moderate strength and better weldability (vs. higher-alloy steels) make it ideal for robust yet relatively lightweight structural parts.
Agricultural Machinery	Shafts, gears, structural supports in tractors, harvesters, irrigation equipment.	Withstands harsh agricultural conditions (moisture, dirt, variable loads). Durability reduces maintenance costs.