Heavy-Duty Custom Carbon Steel Cast Crank Arms | CNC Precision Processed for Engineering Machinery

Product Overview

1. Product Definition

Heavy-Duty Custom Carbon Steel Cast Crank Arms are mission-critical components engineered for high-load power transmission in demanding engineering machinery applications. Manufactured through premium carbon steel casting and finished with advanced CNC precision processing, these crank arms convert rotational motion into controlled linear or reciprocating action with exceptional durability and accuracy.

2. Core Value Proposition

We deliver engineered-to-order power transmission solutions that combine the structural integrity of custom carbon steel casting with the exacting precision of CNC machining. Our crank arms are designed to withstand extreme operational stresses—including high torque, shock loads, and continuous cycling—ensuring reliable performance in the most challenging industrial environments while optimizing machinery efficiency and longevity.

3. Material & Manufacturing Excellence

Advanced Material Science

• Premium Carbon Steel Grades: Utilizing ASTM A27, A148, or equivalent high-yield strength steels with superior fatigue resistance and impact toughness.

• Custom Alloy Options: Available upon request for specific hardness, wear, or corrosion resistance requirements.

• Material Certification: Full traceability with mill test reports confirming chemical composition and mechanical properties.

Precision Manufacturing Process

1. Custom Pattern & Mold Making: Digital or physical patterns created to exact customer specifications.

2. Sand Casting or Investment Casting: Selected based on complexity, volume, and dimensional requirements.

3. Heat Treatment: Normalizing, quenching, and tempering to achieve optimal grain structure and mechanical properties.

4. CNC Precision Machining:

   • Multi-axis CNC milling and turning of bearing journals, pivot holes, and mounting surfaces.

   • Precision boring of crank pins with tolerances within ±0.015 mm.

   • Keyway/spline cutting with specialized CNC gear hobbing or broaching.

5. Surface Enhancement:

   • Shot peening for improved fatigue life.

   • Induction hardening of wear surfaces.

   • Protective coatings (phosphate, black oxide, or plating) available.

4. Technical Specifications

Frequently Asked Questions (FAQs)

1. Product & Materials

Q1: What are the main advantages of custom carbon steel cast crank arms?
A: Our custom carbon steel cast crank arms offer optimal strength-to-weight ratio, design flexibility for complex geometries, and cost-effectiveness for medium-to-large components. Through advanced heat treatment, they achieve mechanical properties close to forged parts while enabling integrated features like reinforcing ribs and custom profiles ideal for low-volume, high-variety engineering machinery applications.

Q2: What customization options are available?
A: We provide comprehensive customization including:

• Design Types: Single-throw, double-throw, multi-cylinder cranks with/without counterweights.

• Connection Methods: Keyed, splined (involute or straight), flanged, or tapered connections.

• Size Range: 50mm to 800mm crank radius (larger sizes available).

• Material Grades: Various carbon steels and alloy steels based on load requirements.

2. Manufacturing & Processing

Q3: What precision levels can your CNC machining achieve?
A: Using multi-axis CNC machines, we achieve:

• Crank Pin Diameter Tolerance: ±0.015 mm

• Main Journal Roundness/Cylindricity: ≤ 0.008 mm

• Keyway/Spline Symmetry: ≤ 0.02 mm

• Surface Finish: Bearing surfaces Ra ≤ 0.8 μm
  All processes include in-line inspection systems for consistency.

Q4: Do you provide heat treatment services? What options are available?
A: Yes, we offer complete heat treatment solutions:

• Standard: Normalizing + Tempering for uniform sorbitic structure.

• Enhanced: Surface induction hardening (2-6mm case depth adjustable).

• Special: Carburizing or nitriding available upon request.

3. Quality Control

Q5: How do you ensure quality?
A: Our four-stage quality control system includes:

1. Raw Material Testing: Spectrochemical analysis + mechanical testing.

2. Casting Process Control: Ultrasonic testing (UT) for internal defects.

3. Machining Inspection: First-article CMM full-dimension inspection + batch sampling.

4. Final Inspection: Magnetic particle testing (MT) + dynamic balancing (G6.3 standard) + visual inspection.
   All test data are traceable with full reports provided.

Q6: What is your balancing standard?
A: Standard balancing grade is ISO 1940 G6.3. For high-speed applications (e.g., generators, compressors), we offer G2.5 precision balancing to significantly reduce vibration and noise.

4. Customization & Services

Q7: What is the typical lead time from design to delivery?
A:

• New Product Development (design, tooling, prototyping): 6-8 weeks

• Batch Production (established process): 8-10 weeks

• Rush Orders: Available upon evaluation

Q8: What information is needed for customization?
A: Please provide:

1. Technical Data: 2D drawings (PDF/DWG) or 3D models (STEP/IGES/SolidWorks)

2. Application Parameters: Operating torque, RPM, load spectrum, environment

3. Quality Requirements: Special inspection standards, certifications

4. Commercial Details: Annual volume, packaging/shipping requirements

Q9: Do you support low-volume prototyping?
A: Absolutely. We offer rapid prototyping services using 3D-printed sand molds or resin patterns, delivering functional prototypes in 2-3 weeks for design verification and testing.

5. Applications & Maintenance

Q10: What equipment are these crank arms used for?
A: They are widely used in:

• Construction Machinery: Excavator swing mechanisms, concrete pump arms

• Mining Equipment: Crusher drives, ball mill transmission systems

• Agricultural Machinery: Large harvester gearboxes, cotton picker spindle drives

• Special Vehicles: Crane hoisting mechanisms, oil workover rig power ends

Q11: How to determine if a crank arm needs replacement?
A: Consider replacement or overhaul when:

• Excessive Vibration: Significant increase in equipment vibration

• Abnormal Noise: Knocking sounds from bearing wear

• Visible Defects: Cracks, severe scoring, or deformation

• Performance Drop: Reduced transmission efficiency

Q12: Do you offer repair/remachining services?
A: Yes. Our remanufacturing services include:

• Wear surface buildup welding

• Bearing journal dimension restoration (laser cladding or electroplating)

• Crack repair welding + heat treatment

• Rebalancing
  This can save 30%-50% compared to new parts.

6. Commercial & After-Sales

Q13: What is your Minimum Order Quantity (MOQ)?
A: MOQ for custom parts is typically 1000 pieces, negotiable based on complexity. For long-term partners or modified standard designs, more flexible arrangements are available.

Q14: How to get a quote?
A: Please send technical requirements to our sales email or via the website form. Our engineering team will contact you within 24 hours with preliminary technical solutions and transparent pricing.