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50CrMo4 / 1.7228 is a high-strength alloy steel belonging to the European standards EN 10083-3 and EN 10250-3. It is widely used in industries requiring superior mechanical properties, such as automotive manufacturing, heavy machinery, aerospace, and oil & gas applications. Its equivalents in other standards include ASTM 4150 from American standard ASTM A29/A29M, 50CrMo from Chinese standard GB/T 3077.
50CrMo4 is part of the Cr-Mo steel series, with a carbon content of 0.46-0.54%, providing higher hardness and strength compared to 42CrMo4. After quenching and tempering, it achieves excellent mechanical properties, including high tensile strength, fatigue resistance, and good toughness.
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AISI 4150 / DIN 50CrMo4 (1.7228) is a high-performance quenching and tempering alloy steel engineered for industries demanding exceptional mechanical strength, fatigue resistance, and toughness under extreme stress. Compliant with international standards including EN 10083-3, EN 10250-3, and ASTM A29/A29M, this alloy belongs to the Cr-Mo (chromium-molybdenum) steel family—renowned for its ability to retain structural integrity in high-load, high-temperature environments.
A key distinction of DIN 50CrMo4 (1.7228) is its precise chemical composition, with a 0.46-0.54% carbon content that enhances hardness and wear resistance, paired with 0.9-1.2% chromium for corrosion resistance and 0.15-0.30% molybdenum to improve heat resistance and toughness. Its equivalent grades across global standards include AISI 4150 (U.S.), 50CrMo (China, per GB/T 3077), and 1.7228 (European material number), ensuring compatibility with international manufacturing workflows.
As a leading manufacturer, Hunan Qilu Steel Co., Ltd. supplies AISI 4150 / DIN 50CrMo4 (1.7228) in diverse forms—from cold-drawn bars to hot-forged blocks—with monthly stocks exceeding 10,000 tons for hot-rolled and forged variants. Each batch undergoes rigorous quality testing, including chemical composition analysis, mechanical property verification, and surface hardness inspection, to meet or exceed industry standards, making it a reliable choice for global buyers seeking consistent performance.
The superior performance of AISI 4150 / DIN 50CrMo4 (1.7228) stems from its carefully optimized properties, tailored to address the demands of high-stress applications. Below is a detailed breakdown of its core features:
After quenching and tempering, DIN 50CrMo4 (1.7228) exhibits exceptional mechanical performance that scales with size, ensuring versatility across component designs:
For small sizes (diameter ≤16mm or thickness ≤8mm): Tensile strength ranges from 1100-1300 Mpa, yield strength minimum 900 Mpa, with ≥9% elongation and ≥40% area reduction—ideal for precision parts like small gears or fasteners.
For medium sizes (16mm < diameter ≤40mm or 8mm < thickness ≤20mm): Tensile strength 1000-1200 Mpa, yield strength minimum 780 Mpa, plus ≥10% elongation and ≥45% area reduction, paired with a minimum impact value of 30 J at room temperature (RT) for resistance to sudden loads.
For large sizes (diameter >160mm or thickness >100mm): Tensile strength 800-950 Mpa, yield strength minimum 550 Mpa, and ≥13% elongation—suited for heavy-duty components like crankshafts or hydraulic cylinders.
For open-die forgings (per EN 10250-3), longitudinal (L) and transverse (Tr) properties are optimized: For diameters ≤160mm, longitudinal tensile strength minimum 800 Mpa and transverse impact value minimum 14 J at RT, ensuring uniform performance across forging orientations.
The alloy’s composition is precisely controlled to balance strength, toughness, and processability, with slight variations across global standards (all values are maximum or range limits):
Element | AISI 4150 | DIN 50CrMo4 (1.7228) | GB/T 3077 50CrMo |
Carbon (C) | 0.48-0.53% | 0.46-0.54% | 0.46-0.54% |
Silicon (Si) | 0.15-0.35% | ≤0.40% | 0.17-0.37% |
Manganese (Mn) | 0.75-1.00% | 0.50-0.80% | 0.50-0.80% |
Phosphorus (P) | ≤0.035% | ≤0.025% | ≤0.030% |
Sulfur (S) | ≤0.040% | ≤0.035% | ≤0.030% |
Chromium (Cr) | 0.80-1.10% | 0.90-1.20% | 0.90-1.20% |
Molybdenum (Mo) | 0.15-0.25% | 0.15-0.30% | 0.15-0.30% |
Notably, DIN 50CrMo4 (1.7228) has a slightly wider molybdenum range than AISI 4150, enhancing its heat resistance for high-temperature applications like exhaust components or industrial furnaces.
AISI 4150 / DIN 50CrMo4 (1.7228) responds exceptionally well to heat treatment, allowing customization of hardness and toughness for specific use cases:
Soft Annealing (+A): Heated to 820-860℃, soaked, then furnace-cooled to a maximum Brinell Hardness (HB) of 248—ideal for pre-machining to reduce tool wear.
Normalizing (+H): Heated to 850-900℃, soaked, then air-cooled to refine grain structure and improve machinability.
Quenching & Tempering (+QT): The most common process: heated to 820-870℃, oil-quenched, then tempered at 540-680℃ (air-cooled). This delivers a Rockwell Hardness (HRC) of 28-32 (common range) for a balance of strength and ductility.
Flame/Induction Hardening: Achieves a maximum HRC of 58 for surface wear resistance—critical for components like gear teeth or bearing surfaces.
Hardenability is consistent across sizes, with restricted ranges (+HL, +HH) for strict applications: For +HH grade, hardness at 50mm from the quenched end is a minimum HRC 42, ensuring deep hardening for thick components.
Hunan Qilu Steel offers AISI 4150 / DIN 50CrMo4 (1.7228) in diverse forms to match manufacturing needs, with tight tolerances for precision:
Cold-Drawn Bars: Diameter Φ3-Φ80mm, length 6000-9000mm, with grinding finish tolerance of +0/+0.05mm and straightness ≤1mm/1000mm.
Hot-Rolled Bars: Diameter Φ16-Φ310mm, length 6000-9000mm, with black rolled tolerance of +0/+1mm for cost-effective large-scale production.
Hot-Forged Bars/Blocks: Bars (Φ100-Φ1200mm, length 3000-5800mm) and blocks (thickness 80-800mm, width 100-2500mm, length 2000-5800mm), with black forged tolerance of +0/+5mm for heavy machinery components.
Common stock sizes for hot-rolled bars include 20mm, 25mm, 30mm, 40mm, 50mm, 60mm, 80mm, and 100mm—with real-time stock updates available via Hunan Qilu Steel’s sales team.
AISI 4150 / DIN 50CrMo4 (1.7228) is a versatile alloy trusted across industries for its ability to withstand high stress, fatigue, and wear. Its applications are tailored to leverage its core properties, including high tensile strength, impact resistance, and heat stability:
In automotive engineering, the alloy is used for critical powertrain and suspension components that endure repeated stress:
Crankshafts & Camshafts: The alloy’s high fatigue resistance (≥30 J impact value at RT) prevents cracking under cyclic loads from engine operation.
Suspension Components: Torsion bars, connecting rods, and universal joints rely on its balanced HRC 28-32 hardness to absorb road vibrations without deformation.
Differential Parts: Gear sets and drive shafts use flame-hardened surfaces (up to 58 HRC) to resist wear from constant meshing.
For construction, mining, and agricultural machinery, DIN 50CrMo4 (1.7228) handles extreme loads and harsh environments:
High-Pressure Cylinders: Used in hydraulic systems for excavators and cranes, thanks to its minimum 700 Mpa yield strength (for 40-100mm sizes) that prevents bursting under high pressure.
Piston Rods & Stamping Dies: The alloy’s excellent toughness (≥13% elongation for large sizes) resists bending and cracking during heavy stamping or lifting operations.
Mining Equipment: Connector pins and gearboxes use its corrosion resistance (from 0.9-1.2% Cr) to withstand dust, moisture, and chemical exposure in mines.
In aerospace, where safety and reliability are paramount, the alloy is specified for components requiring high strength-to-weight ratios:
Landing Gear Components: The alloy’s 1100-1300 Mpa tensile strength (small sizes) supports aircraft weight during takeoff and landing, while its toughness absorbs impact forces.
High-Strength Fasteners: Bolts and nuts for engine casings use QT-treated HRC 28-32 hardness to maintain clamping force at high temperatures (up to 680℃ tempering resistance).
For upstream and downstream oil & gas operations, AISI 4150 / DIN 50CrMo4 (1.7228) resists corrosion and pressure in harsh wellbore or pipeline environments:
Drill Pipe Joints: The alloy’s molybdenum content (0.15-0.30%) enhances heat resistance, making it suitable for high-temperature drilling fluids.
Wellhead Equipment: Valves and flanges use its low phosphorus/sulfur content (≤0.025% P, ≤0.035% S) to avoid brittleness in cold offshore conditions.
The primary difference lies in carbon content: DIN 50CrMo4 (1.7228) has a 0.46-0.54% carbon range, while 42CrMo4 typically has 0.38-0.45%. This higher carbon content gives DIN 50CrMo4 (1.7228) higher tensile strength (up to 1300 Mpa vs. 1100 Mpa for 42CrMo4) and hardness (up to 58 HRC vs. 55 HRC for 42CrMo4). DIN 50CrMo4 (1.7228) also has a wider molybdenum range (0.15-0.30% vs. 0.15-0.25% for 42CrMo4), improving heat resistance. For high-load applications like crankshafts or landing gear, DIN 50CrMo4 (1.7228) is preferred; 42CrMo4 is better for less demanding components like brackets.
Weldability is poor due to its high carbon content (0.46-0.54%)—above the 0.25% threshold where weld cracking risk increases. However, welding is possible with proper pre- and post-weld treatments:
Preheating: Heat the base metal to 200-300℃ to reduce thermal stress.
Welding Consumables: Use low-hydrogen electrodes (e.g., E8018-B2) to avoid hydrogen-induced cracking.
Post-Weld Heat Treatment (PWHT): Temper at 600-650℃ after welding to soften the heat-affected zone (HAZ) and restore toughness. Hunan Qilu Steel recommends consulting a welding engineer for custom procedures, especially for critical applications like aerospace or oil & gas.
The standard process for AISI 4150 / DIN 50CrMo4 (1.7228) is quenching and tempering (QT):
Heat to 820-870℃ (upper end for oil quenching, lower end for water quenching) and soak until uniform temperature.
Quench in oil to avoid cracking (water quenching is possible but increases brittleness risk).
Temper at 540-680℃ (soak 1-2 hours per inch of thickness) and air-cool.
For surface wear resistance, add flame or induction hardening after QT: heat the surface to 850-900℃, quench, and temper lightly (180-220℃) to achieve 55-58 HRC. For pre-machining, use soft annealing (+A) (820-860℃, furnace-cooled) to reduce hardness to ≤248 HB.
Hunan Qilu Steel maintains regular stocks of AISI 4150 / DIN 50CrMo4 (1.7228) in hot-rolled bars (Φ16-Φ310mm) and cold-drawn bars (Φ3-Φ80mm), with common sizes including 20mm, 25mm, 30mm, 40mm, 50mm, 60mm, 80mm, and 100mm. Hot-forged bars (Φ100-Φ1200mm) and blocks are available with 7-10 days of lead time for custom sizes. For urgent orders (e.g., automotive or aerospace), in-stock items can be shipped within 2-3 business days via air or sea freight, with documentation (material test reports, EN 10204 3.1 certificates) provided.
Quality control starts with raw material selection: only high-purity iron ore and alloying elements (Cr, Mo) are used. Each batch undergoes:
Chemical Composition Testing: Via optical emission spectroscopy (OES) to verify C, Cr, Mo, and other elements meet EN 10083-3 standards.
Mechanical Property Testing: Tensile, yield, elongation, and impact tests (per EN ISO 6892-1 and EN ISO 148-1) to confirm strength and toughness.
Hardness Testing: HB (Brinell) for annealed parts and HRC (Rockwell) for QT-treated parts, with checks at 12.5mm below the surface (per EN 10083-1).
Surface Inspection: Visual and ultrasonic testing (UT) to detect cracks, scratches, or inclusions. All products come with EN 10204 3.1 certificates, and custom testing (e.g., NDT, corrosion resistance) is available upon request.
1: Steel equivalent
Country | USA | Europe | China |
Standard | ASTM A29 | EN10083-3 | GB/T3077 |
Grade | 4150 | 50CrMo4/1.7228 | 50CrMo |
2: Chemical composition
Grade | C | Si | Mn | P | S | Cr | Mo |
4150 | 0.48-0.53 | 0.15-0.35 | 0.75-1.00 | 0.035Max | 0.040Max | 0.8-1.1 | 0.15-0.25 |
50CrMo4/1.7228 | 0.46-0.54 | 0.40Max | 0.50-0.80 | 0.025Max | 0.035Max | 0.9-1.2 | 0.15-0.30 |
50CrMo | 0.46-0.54 | 0.17-0.37 | 0.50-0.80 | 0.030Max | 0.030Max | 0.9-1.2 | 0.15-0.30 |
3: Mechanical properties .
Mechanical properties for 50CrMo4 quenching and tempering alloy steel according to EN10083-3.
Size range | Tensile strength | Yield strength | Alongation | Area of reduction | Impact value At RT/J |
d≤16 t≤8 | 1100-1300Mpa | 900Mpa Min | 9% Min | 40% Min | / |
16＜d≤40 8＜t≤20 | 1000-1200Mpa | 780Mpa Min | 10% Min | 45%Min | 30J Min |
40＜d≤100 20＜t≤60 | 900-1100Mpa | 700Mpa Min | 12% Min | 50%Min | 30J Min |
100＜d≤160 60＜t≤100 | 850-1000Mpa | 650Mpa Min | 13% Min | 50%Min | 30J Min |
160＜d≤250 100＜t≤160 | 800-950Mpa | 550Mpa Min | 13% Min | 50%Min | 30J Min |
Sampling and preparation of test pieces for 50CrMo4 quenching and tempering steel.
1): According to EN10083-1, all samples shall be taken at a distance of 12.5mm below the heat treated surface
2): As stipulated in the contract between buyer and seller.
Mechanical properties for 50CrMo4 open die forgings steel according to EN10250-3
Size range | Tensile strength | Yield strength | Alongation | Impact value at RT/J | ||
L | Tr | L | Tr | |||
d≤160 | 800Mpa Min | 550Mpa Min | 13% Min | 9% Min | 25J Min | 14J Min |
160＜d≤330 | 750Mpa Min | 540Mpa Min | 14% Min | 10% Min | 20J Min | 12J Min |
330＜d≤660 | 700Mpa Min | 490Mpa Min | 15% Min | 11% Min | 15J Min | 10J Min |
Remark: L= Longitudinal Tr = Transverse
Sampling and preparation of test pieces for steel forging.
1: According to EN10250-1, all samples shall be taken at a distance of 4/T below the heat treated surface (with a minimum of 20mm and a maximum of 80mm), and t/2 from the end (where t is the equivalent thickness of the thickness of the ruling section of the forging at the time of heat treatment.
2: As stipulated in the contract between buyer and seller.
4: Surface hardness and hardenability.
Heat Treatment | Hardness |
Flame or Induction hardening | 58HRC |
Soft annealed (+A) | HB248Max |
Quenched and tempred (+QT) | HRC28-32(Common Range) |
Where the steel is ordered by using the symbols for normal (+H) or restricted (+HL, +HH) hardenability requirements, the hardenability values should apply below:
Distance in mm from quenched end | ||||||||||||||||
Distance | 1.5 | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 | |
Hardness In HRC + H | max | 65 | 65 | 64 | 64 | 63 | 63 | 63 | 62 | 61 | 60 | 58 | 57 | 55 | 54 | 54 |
min | 58 | 58 | 57 | 55 | 54 | 53 | 51 | 48 | 45 | 41 | 39 | 38 | 37 | 36 | 36 | |
Hardness In HRC + HH | max | 65 | 65 | 64 | 64 | 63 | 63 | 63 | 62 | 61 | 60 | 58 | 57 | 55 | 54 | 54 |
min | 60 | 60 | 59 | 58 | 57 | 56 | 55 | 53 | 50 | 47 | 45 | 44 | 43 | 42 | 42 | |
Hardness In HRC + HL | max | 63 | 63 | 62 | 61 | 60 | 60 | 59 | 57 | 56 | 54 | 52 | 51 | 49 | 48 | 48 |
min | 58 | 58 | 57 | 55 | 54 | 53 | 51 | 48 | 45 | 41 | 39 | 38 | 37 | 36 | 36 | |
Scatter bands for the Rockwell - C hardness in the end quench hardenability test.
5: Supply size & Tolerance & Stock size
Product type | Size range | Length |
Cold drawn bar | Φ3-Φ80mm | 6000-9000mm |
Hot rolled bar | Φ16-Φ310mm | 6000-9000mm |
Hot forged bar | Φ100-Φ1200mm | 3000-5800mm |
Hot rolled plate/sheet | T:3-200mm; W:1500-2500mm | 2000-5800mm |
Hot Forged block | T: 80-800mm; W: 100-2500mm | 2000-5800mm |
Surface Finish | Turned | Milled | Grinding(Best) | Polished(Best) | Peeled(Best) | Black Forged | Black Rolled |
Tolerance | +0/+3mm | +0/+3mm | +0/+0.05mm | +0/+0.05mm | +0/+0.1mm | +0/+5mm | +0/+1mm |
Straighness | 1mm/1000mm max. | 3mm/1000mm max. | |||||
Qilu steel stock hot rolled bar and forged bars more than ten thousands tons every month, below our our stock size.
In China, most of clients will use 42CrMo4 instead of 50CrMo4, so the stocks for 50CrMo4 is small, below is the stock size for hot rolled bar.
20 | 22 | 25 | 28 | 30 | 32 | 35 | 40 | 45 | 50 | 55 | 60 | 65 | 70 | 75 |
80 | 85 | 90 | 95 | 100 | 110 | 120 |
AISI 4150 / DIN 50CrMo4 (1.7228) is a high-performance quenching and tempering alloy steel engineered for industries demanding exceptional mechanical strength, fatigue resistance, and toughness under extreme stress. Compliant with international standards including EN 10083-3, EN 10250-3, and ASTM A29/A29M, this alloy belongs to the Cr-Mo (chromium-molybdenum) steel family—renowned for its ability to retain structural integrity in high-load, high-temperature environments.
A key distinction of DIN 50CrMo4 (1.7228) is its precise chemical composition, with a 0.46-0.54% carbon content that enhances hardness and wear resistance, paired with 0.9-1.2% chromium for corrosion resistance and 0.15-0.30% molybdenum to improve heat resistance and toughness. Its equivalent grades across global standards include AISI 4150 (U.S.), 50CrMo (China, per GB/T 3077), and 1.7228 (European material number), ensuring compatibility with international manufacturing workflows.
As a leading manufacturer, Hunan Qilu Steel Co., Ltd. supplies AISI 4150 / DIN 50CrMo4 (1.7228) in diverse forms—from cold-drawn bars to hot-forged blocks—with monthly stocks exceeding 10,000 tons for hot-rolled and forged variants. Each batch undergoes rigorous quality testing, including chemical composition analysis, mechanical property verification, and surface hardness inspection, to meet or exceed industry standards, making it a reliable choice for global buyers seeking consistent performance.
The superior performance of AISI 4150 / DIN 50CrMo4 (1.7228) stems from its carefully optimized properties, tailored to address the demands of high-stress applications. Below is a detailed breakdown of its core features:
After quenching and tempering, DIN 50CrMo4 (1.7228) exhibits exceptional mechanical performance that scales with size, ensuring versatility across component designs:
For small sizes (diameter ≤16mm or thickness ≤8mm): Tensile strength ranges from 1100-1300 Mpa, yield strength minimum 900 Mpa, with ≥9% elongation and ≥40% area reduction—ideal for precision parts like small gears or fasteners.
For medium sizes (16mm < diameter ≤40mm or 8mm < thickness ≤20mm): Tensile strength 1000-1200 Mpa, yield strength minimum 780 Mpa, plus ≥10% elongation and ≥45% area reduction, paired with a minimum impact value of 30 J at room temperature (RT) for resistance to sudden loads.
For large sizes (diameter >160mm or thickness >100mm): Tensile strength 800-950 Mpa, yield strength minimum 550 Mpa, and ≥13% elongation—suited for heavy-duty components like crankshafts or hydraulic cylinders.
For open-die forgings (per EN 10250-3), longitudinal (L) and transverse (Tr) properties are optimized: For diameters ≤160mm, longitudinal tensile strength minimum 800 Mpa and transverse impact value minimum 14 J at RT, ensuring uniform performance across forging orientations.
The alloy’s composition is precisely controlled to balance strength, toughness, and processability, with slight variations across global standards (all values are maximum or range limits):
Element | AISI 4150 | DIN 50CrMo4 (1.7228) | GB/T 3077 50CrMo |
Carbon (C) | 0.48-0.53% | 0.46-0.54% | 0.46-0.54% |
Silicon (Si) | 0.15-0.35% | ≤0.40% | 0.17-0.37% |
Manganese (Mn) | 0.75-1.00% | 0.50-0.80% | 0.50-0.80% |
Phosphorus (P) | ≤0.035% | ≤0.025% | ≤0.030% |
Sulfur (S) | ≤0.040% | ≤0.035% | ≤0.030% |
Chromium (Cr) | 0.80-1.10% | 0.90-1.20% | 0.90-1.20% |
Molybdenum (Mo) | 0.15-0.25% | 0.15-0.30% | 0.15-0.30% |
Notably, DIN 50CrMo4 (1.7228) has a slightly wider molybdenum range than AISI 4150, enhancing its heat resistance for high-temperature applications like exhaust components or industrial furnaces.
AISI 4150 / DIN 50CrMo4 (1.7228) responds exceptionally well to heat treatment, allowing customization of hardness and toughness for specific use cases:
Soft Annealing (+A): Heated to 820-860℃, soaked, then furnace-cooled to a maximum Brinell Hardness (HB) of 248—ideal for pre-machining to reduce tool wear.
Normalizing (+H): Heated to 850-900℃, soaked, then air-cooled to refine grain structure and improve machinability.
Quenching & Tempering (+QT): The most common process: heated to 820-870℃, oil-quenched, then tempered at 540-680℃ (air-cooled). This delivers a Rockwell Hardness (HRC) of 28-32 (common range) for a balance of strength and ductility.
Flame/Induction Hardening: Achieves a maximum HRC of 58 for surface wear resistance—critical for components like gear teeth or bearing surfaces.
Hardenability is consistent across sizes, with restricted ranges (+HL, +HH) for strict applications: For +HH grade, hardness at 50mm from the quenched end is a minimum HRC 42, ensuring deep hardening for thick components.
Hunan Qilu Steel offers AISI 4150 / DIN 50CrMo4 (1.7228) in diverse forms to match manufacturing needs, with tight tolerances for precision:
Cold-Drawn Bars: Diameter Φ3-Φ80mm, length 6000-9000mm, with grinding finish tolerance of +0/+0.05mm and straightness ≤1mm/1000mm.
Hot-Rolled Bars: Diameter Φ16-Φ310mm, length 6000-9000mm, with black rolled tolerance of +0/+1mm for cost-effective large-scale production.
Hot-Forged Bars/Blocks: Bars (Φ100-Φ1200mm, length 3000-5800mm) and blocks (thickness 80-800mm, width 100-2500mm, length 2000-5800mm), with black forged tolerance of +0/+5mm for heavy machinery components.
Common stock sizes for hot-rolled bars include 20mm, 25mm, 30mm, 40mm, 50mm, 60mm, 80mm, and 100mm—with real-time stock updates available via Hunan Qilu Steel’s sales team.
AISI 4150 / DIN 50CrMo4 (1.7228) is a versatile alloy trusted across industries for its ability to withstand high stress, fatigue, and wear. Its applications are tailored to leverage its core properties, including high tensile strength, impact resistance, and heat stability:
In automotive engineering, the alloy is used for critical powertrain and suspension components that endure repeated stress:
Crankshafts & Camshafts: The alloy’s high fatigue resistance (≥30 J impact value at RT) prevents cracking under cyclic loads from engine operation.
Suspension Components: Torsion bars, connecting rods, and universal joints rely on its balanced HRC 28-32 hardness to absorb road vibrations without deformation.
Differential Parts: Gear sets and drive shafts use flame-hardened surfaces (up to 58 HRC) to resist wear from constant meshing.
For construction, mining, and agricultural machinery, DIN 50CrMo4 (1.7228) handles extreme loads and harsh environments:
High-Pressure Cylinders: Used in hydraulic systems for excavators and cranes, thanks to its minimum 700 Mpa yield strength (for 40-100mm sizes) that prevents bursting under high pressure.
Piston Rods & Stamping Dies: The alloy’s excellent toughness (≥13% elongation for large sizes) resists bending and cracking during heavy stamping or lifting operations.
Mining Equipment: Connector pins and gearboxes use its corrosion resistance (from 0.9-1.2% Cr) to withstand dust, moisture, and chemical exposure in mines.
In aerospace, where safety and reliability are paramount, the alloy is specified for components requiring high strength-to-weight ratios:
Landing Gear Components: The alloy’s 1100-1300 Mpa tensile strength (small sizes) supports aircraft weight during takeoff and landing, while its toughness absorbs impact forces.
High-Strength Fasteners: Bolts and nuts for engine casings use QT-treated HRC 28-32 hardness to maintain clamping force at high temperatures (up to 680℃ tempering resistance).
For upstream and downstream oil & gas operations, AISI 4150 / DIN 50CrMo4 (1.7228) resists corrosion and pressure in harsh wellbore or pipeline environments:
Drill Pipe Joints: The alloy’s molybdenum content (0.15-0.30%) enhances heat resistance, making it suitable for high-temperature drilling fluids.
Wellhead Equipment: Valves and flanges use its low phosphorus/sulfur content (≤0.025% P, ≤0.035% S) to avoid brittleness in cold offshore conditions.
The primary difference lies in carbon content: DIN 50CrMo4 (1.7228) has a 0.46-0.54% carbon range, while 42CrMo4 typically has 0.38-0.45%. This higher carbon content gives DIN 50CrMo4 (1.7228) higher tensile strength (up to 1300 Mpa vs. 1100 Mpa for 42CrMo4) and hardness (up to 58 HRC vs. 55 HRC for 42CrMo4). DIN 50CrMo4 (1.7228) also has a wider molybdenum range (0.15-0.30% vs. 0.15-0.25% for 42CrMo4), improving heat resistance. For high-load applications like crankshafts or landing gear, DIN 50CrMo4 (1.7228) is preferred; 42CrMo4 is better for less demanding components like brackets.
Weldability is poor due to its high carbon content (0.46-0.54%)—above the 0.25% threshold where weld cracking risk increases. However, welding is possible with proper pre- and post-weld treatments:
Preheating: Heat the base metal to 200-300℃ to reduce thermal stress.
Welding Consumables: Use low-hydrogen electrodes (e.g., E8018-B2) to avoid hydrogen-induced cracking.
Post-Weld Heat Treatment (PWHT): Temper at 600-650℃ after welding to soften the heat-affected zone (HAZ) and restore toughness. Hunan Qilu Steel recommends consulting a welding engineer for custom procedures, especially for critical applications like aerospace or oil & gas.
The standard process for AISI 4150 / DIN 50CrMo4 (1.7228) is quenching and tempering (QT):
Heat to 820-870℃ (upper end for oil quenching, lower end for water quenching) and soak until uniform temperature.
Quench in oil to avoid cracking (water quenching is possible but increases brittleness risk).
Temper at 540-680℃ (soak 1-2 hours per inch of thickness) and air-cool.
For surface wear resistance, add flame or induction hardening after QT: heat the surface to 850-900℃, quench, and temper lightly (180-220℃) to achieve 55-58 HRC. For pre-machining, use soft annealing (+A) (820-860℃, furnace-cooled) to reduce hardness to ≤248 HB.
Hunan Qilu Steel maintains regular stocks of AISI 4150 / DIN 50CrMo4 (1.7228) in hot-rolled bars (Φ16-Φ310mm) and cold-drawn bars (Φ3-Φ80mm), with common sizes including 20mm, 25mm, 30mm, 40mm, 50mm, 60mm, 80mm, and 100mm. Hot-forged bars (Φ100-Φ1200mm) and blocks are available with 7-10 days of lead time for custom sizes. For urgent orders (e.g., automotive or aerospace), in-stock items can be shipped within 2-3 business days via air or sea freight, with documentation (material test reports, EN 10204 3.1 certificates) provided.
Quality control starts with raw material selection: only high-purity iron ore and alloying elements (Cr, Mo) are used. Each batch undergoes:
Chemical Composition Testing: Via optical emission spectroscopy (OES) to verify C, Cr, Mo, and other elements meet EN 10083-3 standards.
Mechanical Property Testing: Tensile, yield, elongation, and impact tests (per EN ISO 6892-1 and EN ISO 148-1) to confirm strength and toughness.
Hardness Testing: HB (Brinell) for annealed parts and HRC (Rockwell) for QT-treated parts, with checks at 12.5mm below the surface (per EN 10083-1).
Surface Inspection: Visual and ultrasonic testing (UT) to detect cracks, scratches, or inclusions. All products come with EN 10204 3.1 certificates, and custom testing (e.g., NDT, corrosion resistance) is available upon request.
1: Steel equivalent
Country | USA | Europe | China |
Standard | ASTM A29 | EN10083-3 | GB/T3077 |
Grade | 4150 | 50CrMo4/1.7228 | 50CrMo |
2: Chemical composition
Grade | C | Si | Mn | P | S | Cr | Mo |
4150 | 0.48-0.53 | 0.15-0.35 | 0.75-1.00 | 0.035Max | 0.040Max | 0.8-1.1 | 0.15-0.25 |
50CrMo4/1.7228 | 0.46-0.54 | 0.40Max | 0.50-0.80 | 0.025Max | 0.035Max | 0.9-1.2 | 0.15-0.30 |
50CrMo | 0.46-0.54 | 0.17-0.37 | 0.50-0.80 | 0.030Max | 0.030Max | 0.9-1.2 | 0.15-0.30 |
3: Mechanical properties .
Mechanical properties for 50CrMo4 quenching and tempering alloy steel according to EN10083-3.
Size range | Tensile strength | Yield strength | Alongation | Area of reduction | Impact value At RT/J |
d≤16 t≤8 | 1100-1300Mpa | 900Mpa Min | 9% Min | 40% Min | / |
16＜d≤40 8＜t≤20 | 1000-1200Mpa | 780Mpa Min | 10% Min | 45%Min | 30J Min |
40＜d≤100 20＜t≤60 | 900-1100Mpa | 700Mpa Min | 12% Min | 50%Min | 30J Min |
100＜d≤160 60＜t≤100 | 850-1000Mpa | 650Mpa Min | 13% Min | 50%Min | 30J Min |
160＜d≤250 100＜t≤160 | 800-950Mpa | 550Mpa Min | 13% Min | 50%Min | 30J Min |
Sampling and preparation of test pieces for 50CrMo4 quenching and tempering steel.
1): According to EN10083-1, all samples shall be taken at a distance of 12.5mm below the heat treated surface
2): As stipulated in the contract between buyer and seller.
Mechanical properties for 50CrMo4 open die forgings steel according to EN10250-3
Size range | Tensile strength | Yield strength | Alongation | Impact value at RT/J | ||
L | Tr | L | Tr | |||
d≤160 | 800Mpa Min | 550Mpa Min | 13% Min | 9% Min | 25J Min | 14J Min |
160＜d≤330 | 750Mpa Min | 540Mpa Min | 14% Min | 10% Min | 20J Min | 12J Min |
330＜d≤660 | 700Mpa Min | 490Mpa Min | 15% Min | 11% Min | 15J Min | 10J Min |
Remark: L= Longitudinal Tr = Transverse
Sampling and preparation of test pieces for steel forging.
1: According to EN10250-1, all samples shall be taken at a distance of 4/T below the heat treated surface (with a minimum of 20mm and a maximum of 80mm), and t/2 from the end (where t is the equivalent thickness of the thickness of the ruling section of the forging at the time of heat treatment.
2: As stipulated in the contract between buyer and seller.
4: Surface hardness and hardenability.
Heat Treatment | Hardness |
Flame or Induction hardening | 58HRC |
Soft annealed (+A) | HB248Max |
Quenched and tempred (+QT) | HRC28-32(Common Range) |
Where the steel is ordered by using the symbols for normal (+H) or restricted (+HL, +HH) hardenability requirements, the hardenability values should apply below:
Distance in mm from quenched end | ||||||||||||||||
Distance | 1.5 | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 | |
Hardness In HRC + H | max | 65 | 65 | 64 | 64 | 63 | 63 | 63 | 62 | 61 | 60 | 58 | 57 | 55 | 54 | 54 |
min | 58 | 58 | 57 | 55 | 54 | 53 | 51 | 48 | 45 | 41 | 39 | 38 | 37 | 36 | 36 | |
Hardness In HRC + HH | max | 65 | 65 | 64 | 64 | 63 | 63 | 63 | 62 | 61 | 60 | 58 | 57 | 55 | 54 | 54 |
min | 60 | 60 | 59 | 58 | 57 | 56 | 55 | 53 | 50 | 47 | 45 | 44 | 43 | 42 | 42 | |
Hardness In HRC + HL | max | 63 | 63 | 62 | 61 | 60 | 60 | 59 | 57 | 56 | 54 | 52 | 51 | 49 | 48 | 48 |
min | 58 | 58 | 57 | 55 | 54 | 53 | 51 | 48 | 45 | 41 | 39 | 38 | 37 | 36 | 36 | |
Scatter bands for the Rockwell - C hardness in the end quench hardenability test.
5: Supply size & Tolerance & Stock size
Product type | Size range | Length |
Cold drawn bar | Φ3-Φ80mm | 6000-9000mm |
Hot rolled bar | Φ16-Φ310mm | 6000-9000mm |
Hot forged bar | Φ100-Φ1200mm | 3000-5800mm |
Hot rolled plate/sheet | T:3-200mm; W:1500-2500mm | 2000-5800mm |
Hot Forged block | T: 80-800mm; W: 100-2500mm | 2000-5800mm |
Surface Finish | Turned | Milled | Grinding(Best) | Polished(Best) | Peeled(Best) | Black Forged | Black Rolled |
Tolerance | +0/+3mm | +0/+3mm | +0/+0.05mm | +0/+0.05mm | +0/+0.1mm | +0/+5mm | +0/+1mm |
Straighness | 1mm/1000mm max. | 3mm/1000mm max. | |||||
Qilu steel stock hot rolled bar and forged bars more than ten thousands tons every month, below our our stock size.
In China, most of clients will use 42CrMo4 instead of 50CrMo4, so the stocks for 50CrMo4 is small, below is the stock size for hot rolled bar.
20 | 22 | 25 | 28 | 30 | 32 | 35 | 40 | 45 | 50 | 55 | 60 | 65 | 70 | 75 |
80 | 85 | 90 | 95 | 100 | 110 | 120 |
