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IS 12487:1990 is the Indian Standard (BIS) for spring washers - helical - carbon steel. This standard specifies the material, dimensional, and performance requirements for helical spring washers made from carbon steel. It covers various types including single coil (square and rectangular sections) and double coil, intended for use with bolts, nuts, and screws to prevent loosening due to vibration.
Specifies the requirements for helical spring washers made from carbon steel for general engineering purposes.
ASME B18.21.1-2009ASME - American Society of Mechanical Engineers, USA
HighCurrent
Lock Washers (Inch and Metric)
Covers metric helical spring-lock washers of regular type, among others.
JIS B 1251:2018JSA - Japanese Standards Association, Japan
HighCurrent
Spring lock washers
Specifies requirements for steel spring lock washers for general use.
DIN 127 B:1987DIN - Deutsches Institut für Normung, Germany
HighWithdrawn
Spring lock washers with square ends or with tang ends
Form B (square/plain ends) is dimensionally almost identical to IS 12487.
BS 4464:1969BSI - British Standards Institution, UK
MediumWithdrawn
Specification for spring washers for general engineering and automobile purposes. Metric series
Covers multiple types of spring washers, including the single coil square section type.
Key Differences
≠The specified hardness range in IS 12487 is 430-520 HV, which has a higher minimum value compared to JIS B 1251 (400-500 HV) and the typical range for ASME B18.21.1 (40-50 HRC, approx. 390-513 HV).
≠IS 12487 covers a single series of regular type washers from nominal size M2 to M36. In contrast, ASME B18.21.1 is more comprehensive, including regular, heavy, extra-duty, and high-collar series and a wider size range (M1.6 to M100).
≠Material specification in IS 12487 is defined by a specific chemical composition (e.g., 0.55-0.80% Carbon). ASME B18.21.1 references multiple standard material grades (e.g., SAE 1055-1065) and explicitly allows for other materials like stainless steel and bronze.
Key Similarities
≈The fundamental design is identical across all standards: a single-coil, split helical washer made from a trapezoidal or rectangular cross-section, designed to provide locking action through spring force.
≈For commonly used nominal sizes, the critical dimensions such as inside diameter, outside diameter, and material thickness are highly harmonized and often identical (e.g., for M10: ID 10.2mm, OD 18.1mm, Thickness 2.2mm).
≈All standards mandate essential performance tests to ensure product quality, including a hardness test for strength and spring properties, and a form of brittleness test (typically a twist test) to prevent fracture in service.
≈The primary material of construction is fundamentally the same: a medium-to-high carbon spring steel that is heat-treated (hardened and tempered) to achieve the required mechanical properties.
Parameter Comparison
Parameter
IS Value
International
Source
Hardness
430 - 520 HV
400 - 500 HV
JIS B 1251:2018
Hardness
430 - 520 HV
40 - 50 HRC (approx. 390 - 513 HV)
ASME B18.21.1-2009
Thickness (for M10 washer)
2.2 mm
2.2 mm
ASME B18.21.1-2009
Outside Diameter (for M10 washer)
18.1 mm
18.1 mm
JIS B 1251:2018
Material (Carbon Content)
0.55 - 0.80%
0.55 - 0.66% (for SAE 1060 grade)
ASME B18.21.1-2009
Nominal Size Range (Metric)
M2 to M36
M1.6 to M100
ASME B18.21.1-2009
⚠ Verify details from original standards before use
Key Values4
Quick Reference Values
Required Hardness (Vickers)420 to 520 HV
Required Hardness (Rockwell C)42.5 to 50.5 HRC
Material Grade ReferenceSteel conforming to IS 1570 or IS 4454 (Part 1)
Closing Test RequirementWasher shall not fracture and must show a permanent set
Tables & Referenced Sections
Key Tables
Table 1 - Dimensions of Helical Spring Washers, Single Coil, Square Section ( Type A )
Table 2 - Dimensions of Helical Spring Washers, Single Coil, Rectangular Section ( Type B )
Table 3 - Dimensions of Helical Spring Washers, Double Coil ( Type C )