Dia mm Φ	Dia mm Φ	Dia mm Φ	Dia mm Φ
10	40	76.2	127
12	45	80	130
14	50	85	135
16	55	90	140
18	56	100	150
20	57.15	101.6	152.4
25	60	105	160
28	63	110	170
30	65	115	177.8
35	70	120	180
36	75	125	200
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Top 4140 Round Bar Suppliers for High-Strength Steel Applications

As one of the most trusted 4140 round bar suppliers, we provide high-performance alloy steel bars designed for critical applications requiring strength, toughness, and precision. 4140 round bar is a chromium-molybdenum alloy steel recognized for its excellent mechanical properties and versatility, making it ideal for high-stress environments such as hydraulic and automotive systems.
With a composition of 0.38–0.43% carbon, 0.8–1.1% chromium, and 0.15–0.25% molybdenum, cylinder rods offers exceptional hardenability, allowing for advanced heat treatments like quenching, tempering, and induction hardening. This allows our 4140 round bars to achieve high surface hardness and internal toughness—ideal for precision-engineered parts such as cylinder rods, shafts, and structural components.

We offer 4140 round bars in both hot-rolled and cold-drawn conditions, with dimensional accuracy conforming to f7/f8 external diameter tolerances, surface roughness max Ra 0.2μm, and roundness tolerance of ×1/2. Our products can be further enhanced with hard chrome plating:<Φ22.225mm: min 15μm, ≥Φ24mm: min 20μm. This coating offers excellent wear and corrosion resistance, essential for components exposed to friction, fluid contact, and outdoor environments.

One of the key uses of 4140 round bars is in hydraulic cylinder rod manufacturing. These 4140 round bars require exceptional tensile strength, fatigue resistance, and surface durability to endure constant reciprocating motion under high pressure. 4140 excels in this role due to:
1. High strength and toughness for withstanding axial loads
2. Excellent fatigue life, even in dynamic operations
3. Enhanced wear resistance after induction hardening or chrome plating
4. Outstanding dimensional stability for sealing precision
5. Corrosion resistance when plated, suited for industrial and mobile hydraulics

In addition to hydraulic systems, our 4140 cylinder rods are used in the automotive, aerospace, oil & gas, and heavy machinery sectors—making them a top choice where performance and reliability matter.

We supply standard lengths from 2M to 6M, and diameters ranging from Φ10 ~ Φ200 (1/4” ~ 10”). Available steel grades include JIS G4105 (SCM440), SAE 4140, DIN 42CrMo4, EN 42CrMo4, and EN19. Upon request, we offer induction hardened rods, quenched and tempered bars (QT), and customized surface treatments to meet specific application needs.

As experienced 4140 round bar suppliers, we are committed to delivering precision materials that meet global quality standards for critical, high-strength steel applications. Contact us today to find the right cylinder rod solution for your hydraulic or industrial project.

42CrMo4 Round Bar and EN19 Round Bar for High-Performance Piston Rods

When selecting materials for hydraulic cylinder components, especially cylinder rods, choosing the right steel grade is essential for achieving durability, precision, and performance. 42CrMo4 round bar and EN19 round bar are two of the most reliable alloy steels used in heavy-duty applications, offering superior strength and wear resistance compared to conventional medium carbon steels like CK45.

What Are 42CrMo4 and EN19 Round Bars?

Both 42CrMo4 and EN19 refer to similar chromium-molybdenum alloy steels that are widely used in Europe and internationally under various standards. These steels are equivalent to SAE 4140 and are characterized by:
1. Excellent tensile and yield strength
2. High hardenability and fatigue resistance
3. Excellent response to heat treatment, especially quenching and tempering

As high-strength alloy steels, 42CrMo4 round bar and EN19 round bar are ideal for machining into hydraulic cylinder rods, shafts, and structural machine components.

Why Choose 42CrMo4 or EN19 for Cylinder Rods?

Compared to CK45, 42CrMo4 round bar and EN19 round bar provide higher tensile strength, better resistance to fatigue and wear, and longer operational life—making them ideal for use in high-pressure hydraulic systems, construction machinery, and heavy industrial applications.
Key benefits include:
1. Durability under Load: Withstand high-pressure environments and repetitive loading cycles.
2. Wear-Resistant Surface: Ideal for induction hardening and hard chrome plating, extending rod lifespan.
3. Dimensional Accuracy: Compatible with high-precision surface finishes (Ra ≤ 0.2 μm) and tight tolerances.
4. Surface Treatments: Support for induction hardened layers (1.5 mm), polished chrome plating (15–25 μm), and fine grinding for optimal sealing.

Typical Finishing for Cylinder Rod Applications:
1. Quenched and Tempered (QT) for toughness and strength.
2. Induction Hardening to form a hardened surface while maintaining a ductile core.
3. Hard Chrome Plating for corrosion resistance and seal-friendly surface.
4. Precision Grinding for improved roundness, straightness, and dimensional control.

Conclusion:
Whether listed under42CrMo4 round bar, EN19 round bar, or SAE 4140, these materials provide the mechanical performance necessary for high-demand cylinder rod applications. They outperform CK45 in terms of fatigue strength, wear resistance, and heat treatment capability, making them a superior choice for hydraulic and pneumatic cylinder rods, especially in construction, mining, and industrial automation sectors.

For OEM manufacturers and system designers seeking reliable long-term performance, 42CrMo4 and EN19 round bars are the materials of choice for advanced piston rod production.

Purpose:

SCM 440/4140 Chrome Molybdenum Steel Rod, Induction hardening 4140, 42CrMo4 QT,EN19, 4140 chrome bar, 42CrMo4 en 10083 is the operation for auto parts, injection machine, hydraulic machine, tie bars.

Tolerance of SCM 440/4140 Chrome Molybdenum Steel Rod, Induction hardening 4140, 42CrMo4 QT,EN19, 4140 chrome bar, 42CrMo4 en 10083

Grade of tolerance Dia mm Φ	f		g	h
Grade of tolerance Dia mm Φ	f7	f8	g6	h7	h8	h9
3mm	-0.006 -0.016	-0.006 -0.020	-0.002 -0.008	0 -0.010	0 -0.014	0 -0.025
3mm-6mm	-0.010 -0.022	-0.010 -0.028	-0.004 -0.012	0 -0.012	0 -0.018	0 -0.030
6mm-10mm	-0.013 -0.028	-0.013 -0.035	-0.005 -0.014	0 -0.015	0 -0.022	0 -0.036
10mm-18mm	-0.016 -0.034	-0.016 -0.043	-0.006 -0.017	0 -0.018	0 -0.027	0 -0.043
18mm-30mm	-0.020 -0.041	-0.020 -0.053	-0.007 -0.020	0 -0.021	0 -0.033	0 -0.052
30mm-50mm	-0.025 -0.050	-0.025 -0.064	-0.009 -0.025	0 -0.025	0 -0.039	0 -0.062
50mm-80mm	-0.030 -0.060	-0.030 -0.079	-0.010 -0.029	0 -0.030	0 -0.046	0 -0.074
80mm-120mm	-0.036 -0.071	-0.036 -0.090	-0.012 -0.034	0 -0.035	0 -0.054	0 -0.087
120mm-180mm	-0.043 -0.083	-0.043 -0.106	-0.014 -0.039	0 -0.040	0 -0.063	0 -0.100
180mm-250mm	-0.050 -0.096	-0.050 -0.122	-0.015 -0.044	0 -0.046	0 -0.072	0 -0.115
250mm-315mm	-0.056 -0.108	-0.056 -0.137	-0.017 -0.049	0 -0.052	0 -0.081	0 -0.130
315mm-400mm	-0.062 -0.119	-0.062 -0.151	-0.018 -0.054	0 -0.057	0 -0.089	0 -0.140
400mm-500mm	-0.068 -0.131	-0.068 -0.165	-0.020 -0.060	0 -0.063	0 -0.097	0 -0.155

(unit)µ=0.001mm

Chrome Molybdenum Steel, Chromium-Molybdenum Steels, SCM 440/4140 Chrome Molybdenum Steel Rod, Induction hardening 4140, 42CrMo4 QT,EN19, 4140 chrome bar, 42CrMo4 en 10083

Symbol	Chemical Analysis (%)								Equivalent AISI No.
Symbol	C	Si	Mn	P	S	Ni	Cr	Mo	Equivalent AISI No.
SCM440	0.38-0.43	0.15-0.35	0.60-0.85	≤0.030	≤0.030	—	0.90-1.20	0.15-0.30	4140

If you are interested in our Chrome Molybdenum Steel (Chromium-Molybdenum Steels), please contact us online. Related Keyword: Hydraulic Piston Rod, Cylinder Piston Rod

4140 Round Bar Suppliers, 42CrMo4 Round Bar, EN19 Round Bar, Cylinder Rod