7Cr17 Steel (68Cr17) High Carbon Stainless Steel

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68Cr17 7Cr17 stainless steel kitchen knife
A kind of stainless steel kitchen knife made from 7Cr17 steel

Introduction

68Cr17 (7Cr17 steel) is a Chinese high barbon chromium martensitic stainless steel with a higher quenching hardness than 2Cr13 steel. 7Cr17 stainless steel has high strength and hardness under quenching and tempering conditions, and has both stainless and corrosion resistance.

Note: 68Cr17 is the new designation of 7Cr17, in other words, 68Cr17 = 7Cr17 steel.

7Cr17 Steel is generally used to manufacture corrosion-resistant parts such as knives, gauges, shafts, valves, and components that require corrosion and resistance to dilute oxidizing acids, organic acids and salts.

Datasheet & Spacification

The following tables list the 7Cr17 stainless steel datasheet and specification such as chemical composition, physical properties and mechanical properties, etc.

7Cr17 Stainless Steel Chemical Composition

The composition of 7Cr17 high carbon stainless steel is displayed in the following table.

Chemical Composition %
Steel GradeCSi (≤)Mn (≤)P (≤)S (≤)CrNi (≤)Mo (≤)
7Cr17
(68Cr17)
0.60-0.751.001.000.0400.03016.00-18.00(0.60)(0.75)

The values in parentheses are the maximum values that can be added or allowed.

Mechanical Properties

For steel plate and strip after annealing

  • Extension strength: ≥245 MPa
  • Tensile strength: ≥590 MPa
  • Elongation: ≥15%
  • Material HRC hardness: ≤ 25
  • HV Hardness: ≤269
  • HBW: ≤255

For steel bar

  • Material HRC Hardness:≥ 54 (Quenched and tempered);
  • Material HBW Hardness: ≤ 255 (Annealing)

Physical Properties

  • Density (g/cm3): 7.78
  • Melting point: 1371-1508℃
  • Specific heat capacity (J/Kg·K): 160 at 0-100℃
  • Thermal conductivity (W/m·K): 21.2 at 100℃
  • Coefficients of linear thermal expansion (10-6/K):
    • 10.2 (0-100℃)
    • 11.7 (0-500℃)
  • Electrical Resistivity (μΩ·m): 0.6 at 20℃
  • Longitudinal modulus of elasticity (kN/mm2): 200 at 20℃

Typical Heat Treatment Specification

For steel bar

  • Annealing: 800 – 920 ℃ (Slow cooling)
  • Quenching: 1010 – 1070 ℃ (Oil cooling)
  • Tempering: 100 – 180 ℃ (Rapid cooling)

For steel plate and strip

  • Annealing: About 750℃ (rapid cooling) or 800 – 900℃ (slow cooling)
  • Quenching: 1010 – 1070℃ (rapid cooling)
  • Tempering: 150 – 400 ℃ (Air cooling)

Equivalent Grade

68Cr17 (7Cr17 steel) equivalent to US ASTM AISI SAE, Japanese JIS standard for reference.

7Cr17 materail equivalent
ChinaUSAJapanGermanyFranceUKISO
StandardGradeStandardGrade (UNS)StandardGradeStandardGradeStandardGradeStandardGradeStandardGrade
GB/T 1220;
GB/T 3280
7Cr17AISI,
ASTM A276/A276M
440A (S44002)JIS G4303SUS 440A

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