DIN 127 spring lock washers are produced in spring steel to DIN 267 Part 26, stainless steel A2 (equivalent to 304), A4 (equivalent to 316), and 316Ti, with silicon bronze, titanium, and aluminum alloy offered as specialty variants across a nominal size range of M2 to M100 [S1][S2][S4][S6].
The standard defines two end geometries, Type A with tang ends and Type B with square ends, and the washers are explicitly limited to bolt/nut assemblies of property class 5.8 or lower as defined by ISO 898-1 [S3][S5]. Higher property classes require alternative locking geometries such as wave or conical spring washers, not DIN 127 rectangular-section units [S3].
Standard Material Families and Designations
Spring steel to DIN 267-26 is the baseline material and the most widely stocked DIN 127 grade, used where corrosion resistance is not a primary design driver [S1][S8]. The fastener designation in this material reads FSt (Federstahl), per the DIN 267-26 technical supply conditions that govern hardness, spring force, and permanent set behavior of rectangular-section spring washers [S8].
For stainless service, A2 (304) and A4 (316) are the two grades listed in the DIN 127A material legend, with 316Ti explicitly added in Aspen Fasteners' Type B product range as a higher-temperature alternative to standard A4 [S1][S2]. The 316Ti variant stabilizes against intergranular corrosion at elevated service temperatures via titanium stabilization of the austenitic matrix, which makes it the preferred choice for heat-treat fixtures, exhaust flanges, and chemical service above the standard 316 sensitization window [S1].
Beyond the four primary DIN-listed materials, manufacturer catalogs extend the range to silicon bronze (for marine and spark-resistant applications), grade 2 or grade 5 titanium alloy (where weight or galvanic compatibility with titanium assemblies is required), aluminum alloy (low-mass applications), and copper (specialty electrical/thermal conductivity use cases) [S4][S6]. A complete OEM material cross-reference is published in the spring washer encyclopedia entry.
Mechanical Performance: Spring Force, Permanent Set, and Hardness
IS 3063:1994, the Indian Standard aligned with DIN 127:1987, specifies the spring force and permanent set test methodology that the steel grades must satisfy, including a permanent load test incorporated directly from the DIN 127 revision [S3]. The spring lock washer's function is to compensate for tension loss caused by bolt embedment and creep, not to provide a friction-based locking action in shear-loaded joints [S3].
Standard finishes on steel DIN 127B washers are plain (oil-quenched spring steel), zinc plated (clear/blue), and zinc yellow plated (chromate conversion for additional corrosion resistance), with the zinc yellow option used in mild outdoor or mildly corrosive atmospheres [S4][S9]. For higher-corrosion or hygienic service, A2 or A4 stainless is specified instead of plated steel, since plating is a sacrificial coating that can fail in chloride-rich environments [S4].
The key dimensional driver for spring performance is the rectangular cross-section (width b, thickness s), with the s dimension carrying a tight ±0.1 to ±0.25 mm tolerance depending on nominal size: M3 to M5 at ±0.1 mm, M6 to M20 at ±0.15 to ±0.2 mm, and M24 to M100 at ±0.25 mm [S1][S2]. The free height h varies from a 1.2 mm minimum at M2 to 18.9 mm at M72, with consistent 1.2 to 1.6 ratio between min and max free height across most size steps [S1].
Size Range, Dimensional Table, and Mass Data
The DIN 127 size envelope runs from M2 (inner diameter 2.1 to 2.4 mm, weight 0.033 kg per 1000 pieces) through M100 (inner diameter 101 to 102.5 mm, weight 318 kg per 1000 pieces) with the most common industrial sizes M6, M8, M10, M12, and M16 representing the bulk of catalog stock [S1][S2][S5].
For an M10 DIN 127B washer, the canonical dimensions are: inner diameter 10.2 to 10.7 mm, outer diameter 18.1 mm max, section width 3.5 ±0.2 mm, section thickness 2.2 ±0.15 mm, free height 4.4 to 5.2 mm, and reference mass 2.53 kg per 1000 pieces at the 7.85 kg/dm³ steel density [S1][S5]. The same M10 in A4 stainless is geometrically identical; only the material changes the corrosion behavior and the spring force, since stainless grades have lower modulus and yield strength than hardened spring steel.
Material and finish selection for typical M16 rectangular-profile spring washers is documented in detail in the DIN 127B M16 product range listing, which carries Aluminum, A2, A4, and spring steel options with per-100-piece weight data [S7].
Comparison of Material Options on Selection Criteria
The four primary materials are best compared against four decision criteria relevant to fastener specification: corrosion resistance, service temperature, cost relative to spring steel, and galvanic compatibility with the bolt [S1][S2][S4][S6].
Spring steel (FSt to DIN 267-26) offers the highest spring force per cross-section and lowest cost, but requires a plating or coating for any corrosive exposure, and is not suitable for stainless bolt assemblies due to galvanic mismatch. A2 stainless (304 equivalent) provides general-purpose corrosion resistance suitable for indoor, food-grade, and mildly outdoor atmospheres, with service temperatures up to approximately 425 °C before sensitization becomes a concern. A4 stainless (316 equivalent) extends corrosion resistance to chloride-rich environments such as marine, swimming pool, and chemical exposures, with similar service temperature limits. 316Ti adds titanium stabilization for sustained exposure in the 500 to 800 °C sensitization window, which standard A4 does not handle reliably [S1].
Silicon bronze sits in a separate niche: it is specified where spark resistance, marine biofouling resistance, or non-magnetic behavior is required, accepting a lower spring force per cross-section than hardened spring steel [S4][S6]. Titanium grade 2 or grade 5 is used only where galvanic compatibility with a titanium bolt assembly, low mass, or non-magnetic requirements justify the material premium [S6]. The fastener-side material family decision is often the same decision made for the sealing washer choice in the same joint, since dissimilar metals in one bolted stack create predictable galvanic issues.
Application Limits, Misuse Patterns, and Correct Spec Boundaries
DIN 127 washers are unsuitable for property class 8.8, 10.9, or 12.9 bolt assemblies, where the spring force developed by the rectangular section is insufficient to maintain clamping load against the higher preload levels of these grades [S3]. Wave-form, conical, or disc-spring washers are used for property classes above 5.8, not the DIN 127 single-coil rectangular geometry [S3].
The standard also explicitly states that the locking function is based on spring-back, not friction: if transverse forces overcome the friction between clamped components, the assembly can still loosen despite the split lock washer being installed [S3]. This is a documented limitation of the geometry, and a sealing washer or dedicated thread-locking feature is the correct complementary choice for vibration-loaded joints.
For stainless DIN 127 washers on stainless bolts, the spring force is typically 30 to 50 % lower than the equivalent spring-steel part at the same cross-section, due to the lower yield strength of austenitic grades. Engineers who specify stainless for corrosion reasons should verify that the resulting spring force still meets the joint's preload-loss budget before substitution.
Standards Mapping and Cross-Reference
DIN 127 (publication date 10/1987, superseding the 12/1970 issue) has been formally withdrawn as a current DIN standard, but remains the controlling document for spring steel rectangular-section washers worldwide and is still cited by every major OEM catalog [S5][S8]. The IS 3063:1994 Indian Standard is technically aligned with DIN 127:1987 in scope, permanent set test, and permanent load test, with size coverage from 2 to 100 mm [S3].
Steel grades used in DIN 127 washers are governed by DIN 267 Part 26, which is the technical supply condition standard for spring-steel fasteners, covering hardness ranges, surface condition, and spring force acceptance criteria [S3][S8]. The dimensional cross-reference for related joining components in pressure and flow service is documented separately in the industrial valve and pressure sensor encyclopedia entries, where bolted-joint integrity on process equipment follows the same class 5.8 boundary defined in DIN 127.
Trackable signal: monitor the Beuth Verlag status of any DIN 127 successor document; as of 2026-10-04, no superseding DIN or ISO standard has been published to replace the withdrawn DIN 127, and global OEM catalogs continue to cite the 1987 issue verbatim [S1][S2][S4][S5]. Related machining and joining guidance is published in the article on closed-loop machining with in-process probing, which covers the metrology side of fastener stack-up verification.