What are Grades 1050/1055?

Grades 1050 and 1055 are high-carbon steels at the upper limit of plain carbon grades. These ASTM A519 1050 1055 tubes are used where wear resistance and spring properties are needed. They get their high hardness from heat treatment. Grade 1050 is a high-carbon grade that has versatile applications. It has 0.48–0.55% carbon. As it has great fatigue strength, grade 1055 with 0.50–0.60% carbon is often used for springs.

ASTM A519 Grade 1050, 1055 Tube Specifications

To ensure proper material selection for high-hardness applications, refer to the ASTM A519 Grade 1050 and 1055 tube specifications detailed below:

Standard ASTM A519 / ASME SA 519
Grade 1050, 1055
UNS Number G10500, G10550
Manufacturing Type Seamless Hot Finished / Cold Drawn
Conditions HR (Hot Rolled), CD (Cold Drawn), SR (Stress Relieved), QT (Quenched & Tempered)
Outside Diameter (OD) Up to 1800 mm
Wall Thickness Up to 250 mm
Length Single Random, Double Random, Cut Length
Form Round, Square, Rectangular, Special Sections

ASTM A519 Grade 1050, 1055 Tube Chemical Composition

The following table outlines the chemical composition requirements for ASTM A519 Grade 1050 and 1055 high-carbon steel tubing:

Grade Carbon (C) % Manganese (Mn) % Phosphorus (P) % Sulfur (S) %
1050 0.48 - 0.55 0.60 - 0.90 0.040 max 0.050 max
1055 0.53 - 0.60 0.60 - 0.90 0.040 max 0.050 max

ASTM A519 Grade 1050, 1055 Tube Mechanical Properties

The following table presents the mechanical properties for ASTM A519 Grade 1050 and 1055 in different heat treatment conditions:

Tensile Strength Yield Strength Elongation Hardness (HBW) Impact Strength
620 – 760 MPa 350 – 460 MPa 10 – 20% 167 – 217 Good (varies by heat treatment)

Heat Treatment

ASTM A519 Grade 1050 and 1055 require precise heat treatment control to achieve high hardness without cracking. The critical parameters are outlined below:

  • Anneal: 790-845°C (1450-1550°F), slow cool
  • Normalise: 845-900°C (1550-1650°F)
  • Harden: 800-845°C (1475-1550°F), water or oil quench
  • Temper: 200-540°C (400-1000°F)

Warning: Susceptible to quench cracking. Uniform heating and proper quench technique are essential.

Welding Considerations

Welding is difficult and generally not recommended for these high-carbon grades due to the following reasons:

  • Very high carbon equivalent
  • High crack sensitivity

If welding is required:

  • Preheat 260-315°C (500-600°F)
  • Use low-hydrogen electrodes
  • Post-weld heat treatment is mandatory
  • Consider mechanical fastening alternatives

Applications

The ASTM A519 1050 and A519 1055 tubes serve 3 applications that require high hardness and wear resistance:

Springs

These high-carbon tubes are ideal for coil springs, leaf springs and other spring parts that need to be strong enough to handle a lot of wear and tear.

Wear Components

The 1050 and 1055 grades have a high hardness that is ideal for rollers, wear plates, and other parts that are prone to abrasive wear.

Hand Tools

Screwdriver blades, wrenches, and hand tool components use these grades for their combination of hardness and toughness when properly heat-treated.

Frequently Asked Questions

  • What is the maximum hardness of 1050/1055?

    ASTM A519 1050 can achieve HRC 58 maximum, and A519 1055 can reach HRC 62.