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 or 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.

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 of 7Cr17 Steel

For steel plate and strip

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

For steel bar

  • Material HRC Hardness:≥ 54 (Quenching and tempering);
  • Material HBW Hardness: ≤ 255 (Annealing)

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 or 7Cr17 steel equivalent to US ASTM, Japanese JIS standard for reference.

7Cr17 materail equivalent
ChinaUSAGermanyJapanFranceUKISO
StandardGradeStandardGrade (UNS)StandardGradeStandardGradeStandardGradeStandardGradeStandardGrade
GB/T 1220;
GB/T 3280;
GB/T 20878
7Cr17AISI,
ASTM A276/A276M
440A (S44002)JIS G4303SUS 440A

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