Introduction to ASTM B168:
ASTM B168 is a standard specification established by the American Society for Testing and Materials (ASTM) that outlines the requirements for nickel-chromium-iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), nickel-chromium-cobalt-molybdenum alloys (UNS N06617), nickel-iron-chromium-tungsten alloys (UNS N06674), and nickel-chromium-molybdenum-copper alloy (UNS N06235) plate, sheet, and strip.
Included Grades and Chemical Composition:
ASTM B168 encompasses several grades of nickel alloys, each with its unique chemical composition. Here are some common ones:
1. UNS N06600 (Inconel 600, 2.4816): Typically composed of nickel, chromium, and iron, with additions of manganese, copper, and carbon.
2. UNS N06601 (Inconel 601, 2.4851): Primarily consists of nickel, chromium, and aluminum, with controlled amounts of iron.
3. UNS N06603 (Inconel 603XL): Composed of nickel, chromium, and iron, with additions of aluminum and titanium.
4. UNS N06617 (Inconel 617): Contains nickel, chromium, cobalt, and molybdenum, along with smaller amounts of aluminum and titanium.
5. UNS N06674 (Inconel 617): Comprises nickel, chromium, iron, and tungsten, with traces of manganese, silicon, and carbon.
6. UNS N06235 (Haynes 625): Nickel-based alloy with significant amounts of chromium, molybdenum, and niobium, along with smaller additions of iron and cobalt.
Mechanical Properties:
The mechanical properties of ASTM B168 alloys vary depending on the grade, thickness, and heat treatment. Typical mechanical properties include tensile strength, yield strength, elongation, and hardness.
ASME SB 168 Size Range and Tolerances for Plates and Coils:
- Plates: Thickness range from 0.1875 inches to 4.000 inches, width up to 48 inches, and length up to 144 inches.
- Coils: Thickness range from 0.002 inches to 0.187 inches, width up to 48 inches, and coil weights up to 10,000 pounds.
Tolerances for dimensions such as thickness, width, and length are specified within the standard to ensure product uniformity and quality.
Permissible Variations in Thickness of B168 Sheet and Strip
| SheetA | ||||
| Specified Thickness,in.(mm) | Hot-Rolled | Cold-Rolled | ||
| 48 (1220) and Under |
Over 48 to 60 (1220 to 1520), incl |
48(1220) and Under |
Over 48 to 60 (1220 to 1520), incl |
|
| 0.018 to 0.025 (0.5 to 0.6),incl | 0.003 (0.08) | 0.004 (0.10) | 0.002(0.05) | 0.003 (0.08) |
| Over 0.025 to 0.034 (0.6 to 0.9),incl | 0.004 (0.10) | 0.005 (0.13) | 0.003 (0.08) | 0.004 (0.10) |
| Over 0.034 to 0.043 (0.9 to 1.1),incl | 0.005 (0.13) | 0.006 (0.15) | 0.004 (0.10) | 0.005 (0.13) |
| Over 0.043 to 0.056(1.1 to 1.4),incl | 0.005 (0.13) | 0.006(0.15) | 0.004 (0.10) | 0.005 (0.13) |
| Over 0.056 to 0.070 (1.4 to 1.8),incl | 0.006 (0.15) | 0.007 (0.18) | 0.005 (0.13) | 0.006 (0.15) |
| Over 0.070 to 0.078 (1.8 to 1.9),incl | 0.007 (0.18) | 0.008 (0.20) | 0.006 (0.15) | 0.007 (0.18) |
| Over 0.078 to 0.093 (1.9 to 2.4),incl | 0.008 (0.20) | 0.009 (0.23) | 0.007 (0.18) | 0.008 (0.20) |
| Over 0.093 to 0.109 (2.4 to 2.8),incl | 0.009 (0.23) | 0.010 (0.25) | 0.007 (0.18) | 0.009 (0.23) |
| Over 0.109 to 0.125 (2.8 to 3.2),incl | 0.010 (0.25) | 0.012 (0.31) | 0.008 (0.20) | 0.010 (0.25) |
| Over 0.125 to 0.140 (3.2 to 3.6),incl | 0.012 (0.31) | 0.014 (0.36) | 0.008 (0.20) | 0.010 (0.25) |
| Over 0.140 to 0.171 (3.6 to 4.3),incl | 0.014 (0.36) | 0.016 (0.41) | 0.009 (0.23) | 0.012 (0.31) |
| Over 0.171 to 0.187 (4.3 to 4.8),incl | 0.015 (0.38) | 0.017 (0.43) | 0.010 (0.25) | 0.013 (0.33) |
| Over 0.187 to 0.218 (4.8 to 5.5),incl | 0.017 (0.43) | 0.019 (0.48) | 0.011 (0.28) | 0.015 (0.38) |
| Over 0.218 to 0.234 (5.5 to 5.9),incl | 0.018(0.46) | 0.020 (0.51) | 0.012 (0.31) | 0.016 (0.41) |
| Over 0.234 to 0.250 (5.9 to 6.4),incl | 0.020 (0.51) | 0.022(0.56) | 0.013 (0.33) | 0.018 (0.46) |
| Cold-Rolled StripA,B | ||||
| Specified Thickness,in.(mm) Widths 12 in.(305 mm)and under,plus and minus | ||||
| Up to 0.050(1.27),inc | 0.0015 (0.038) | |||
| Over 0.050 to 0.093 (1.27 to 2.39),incl | 0.0025 (0.063) | |||
| Over 0.093 to 0.125 (2.39 to 3.18),incl | 0.004 (0.11) | |||
A Measured 3⁄8 in. (9.5 mm) or more from either edge except for strip under 1 in. (25.4 mm) in width which is measured at any place.
B Standard sheet tolerances apply for thicknesses over 0.125 in. (3.2 mm) and for all thicknesses of strip over 12 in. (305 mm) wide.
Permissible Variations in Width of B168 Sheet and Strip
| Specified Thickness,in.(mm) | Specified Width,in. (mm) | Permissible Vari | ations in Specified Width,in.(mm) |
| + | - | ||
| Sheet | |||
| Up to 0.250 (6.35) | ALL | 0.125 (3.18) | 0 |
| StripA | |||
| Under 0.075(1.9) | Up to 12 (305),incl | 0.007 (0.18) | 0.007 (0.18) |
| Over 12 to 48 (305 to 1219),incl | 0.062(1.6) | 0 | |
| 0.075 to 0.100(1.9 to 2.5),incl | Up to 12 (305),incl | 0.009 (0.23) | 0.009 (0.23) |
| Over 12 to 48 (305 to 1219),incl | 0.062(1.6) | 0 | |
| Over 0.100 to 0.125(2.5 to 3.2),inc | Up to 12 (305),incl | 0.012 (0.30) | 0.012 (0.30) |
| Over 12 to 48 (305 to 1219),incl | 0.062(1.6) | 0 | |
| Over 0.125 to 0.160 (3.2 to 4.1),incl | Up to 12 (305),incl | 0.016 (0.41) | 0.016 (0.41) |
| Over 12 to 48 (305 to 1219),incl | 0.062(1.6) | 0 | |
| Over 0.160 to 0.187 (4.1 to 4.7),incl | Up to 12 (305),incl | 0.020 (0.51) | 0.020 (0.51) |
| Over 12 to 48 (305 to 1219),incl | 0.062(1.6) | 0 | |
| Over 0.187 to 0.250 (4.7 to 6.4),inc | Up to 12 (305),incl | 0.062(1.6 | 0.062(1.6) |
| Over 12 to 48 (305 to 1219),incl | 0.062(1.6) | 0.062(1.6) | |
ASME SB 168 Plate Quality Inspection and Testing:
Quality inspection and testing methods are crucial to ensuring compliance with ASTM B168 standards. Common tests include:
- Chemical Composition Analysis: Performed using techniques such as optical emission spectroscopy (OES) or inductively coupled plasma (ICP) analysis.
- Mechanical Testing: Involves tensile testing, hardness testing, and impact testing to assess mechanical properties.
- Dimensional Inspection: Utilizes instruments like calipers, micrometers, and gauges to verify dimensions and tolerances.
- Non-Destructive Testing (NDT): Includes methods like ultrasonic testing (UT) and radiographic testing (RT) to detect internal defects without compromising the integrity of the material.
Related Reference Standards:
- ASTM B906 Standard Specification for General Requirements for Flat-Rolled Nickel and Nickel Alloys Plate, Sheet, and Strip
- B 166 Specification for Nickel-Chromium-Iron Alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, and N06045)* and Nickel-Chromium-Cobalt Molybdenum Alloy (UNS N06617) Rod, Bar, and Wire
- B 880 Specification for General Requirements for Chemical Check Analysis Limits for Nickel, Nickel Alloys and Cobalt Alloys
- E 8 Test Methods for Tension Testing of Metallic Materials
- E 10 Test Method for Brinell Hardness of Metallic Materials
- E 18 Test Methods for Rockwell Hardness of Metallic Materials
- E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
- E 38 Methods for Chemical Analysis of Nickel-Chromium and Nickel-Chromium-Iron Alloys4
- E 112 Test Methods for Determining Average Grain Size
- E 140 Hardness Conversion Tables for Metals Relationship Among Brinell Hardness, Vickers Hardness, Rockwell Hardness, Superficial Hardness, Knoop Hardness, and Scleroscope Hardness
Conclusion:
ASTM B168 serves as a comprehensive standard for nickel and nickel alloy plate, sheet, and strip, providing specifications for various grades, chemical compositions, mechanical properties, size ranges, tolerances, and quality control measures. Adhering to these standards ensures the reliability and performance of materials in diverse industrial applications.
