An official JIS B 5012 spring range uses the code SR for high-deflection springs. Vardhman's page does not state JIS B 5012 or define SR. Treat high-deflection status as unverified until Vardhman supplies its SR catalogue, standard reference or supplier certificate.
The live page does not claim JIS B 5012 compliance. Because SR is used as a JIS B 5012 high-deflection code by an official spring manufacturer, Vardhman should confirm whether its dimensions, tolerances, rate and identification follow that standard. Do not assume compliance from the name alone.
The Vardhman page does not state a colour. Third-party listings or other manufacturers may associate SR with a colour, but colour coding is not universal and should not be imported into Vardhman's product data. Confirm colour, coating and load class from the exact part number.
The page calls it a high-force or heavy-load spring but does not publish a duty class, rate or force table. An official JIS B 5012 SR range is described as high deflection rather than a universal load class. Use exact part-number load/deflection data.
Yes. The live Vardhman page states that the SR Series is manufactured with rectangular wire. The page should still publish the actual wire section, end treatment, tolerances and part-number dimensions because rectangular wire alone does not define load, rate or life.
The live page lists brass, aluminium, alloy steel, carbon steel and copper. Industrial die springs are manufactured from high-tensile alloy or carbon spring steel such as 50CrV4, 55CrSi or SAE 9254. Brass, aluminium and copper are unsuitable for high-force die springs and should be removed from the core specification.
No. Non-ferrous metals lack the fatigue strength and elastic limit required for high-duty die springs. They should be deleted from the primary specification unless Vardhman offers specialized light-duty or corrosion-resistant non-magnetic products.
This text is ambiguous because it confuses wire cross-section with spring body shape or end-face squaring. Rectangular-wire die springs are coiled into a cylindrical spring body with ground flat ends. The description should be revised for clarity.
Die springs are designed to fit inside a specified hole diameter (Dh). The spring's actual outside diameter is manufactured slightly smaller than Dh to allow radial expansion during compression without binding against pocket walls.
The inside diameter (Dd) is designed to clear a specific guide rod diameter. The guide rod prevents lateral buckling during long stroke operation. Ensure the guide rod matches the catalog specification.
Free length (L0) is the uncompressed overall length. Combined with spring rate, it determines initial preload force, allowable working stroke and solid height. Precise millimeter lengths must be specified in tool designs.
The live page does not publish spring rate values. Spring rate varies by outer diameter, wire section and free length. A part-number table listing rate (N/mm or kgf/mm) is required for proper engineering calculations.
A minimum preload of 3% to 5% of free length (or at least 1–2 mm) is recommended to keep the spring seated firmly in its pocket, prevent shock impact upon stroke initiation, and eliminate chatter or rattle during fast cycling.
Working stroke equals working compression minus preload deflection. Depending on the specific duty rating, allowable deflection limits usually range from 30% to 50% of free length for long-life operation.
Total Compression = Preload Deflection + Working Stroke. This sum must never exceed the maximum recommended catalog deflection percentage for the specific series to prevent premature settling or breakage.
Long-life deflection is the conservative compression ratio that permits up to 1,000,000 operational cycles without significant set or fatigue cracking.
Maximum operating deflection is the peak recommended compression limit for shorter production runs (e.g. 300,000 to 500,000 cycles). Operating beyond this limit causes rapid fatigue failure.
Solid deflection is the maximum physical compression where all active coils touch each other. Operating a spring near solid height causes severe inter-coil impact, permanent set and immediate failure.
Spring Force = Spring Rate × Deflection. Calculate force at preload compression and at peak working stroke to ensure the spring meets tool operating requirements.
When multiple identical springs are installed in parallel, Total Force = Force per Spring × Number of Springs. Ensure all parallel springs share identical free length and rate to distribute load evenly.
This text is a placeholder indicating that force and compression vary by size and load class. It should be replaced with a structured part-number table showing rate, deflection limits and force for each item.
Rectangular-wire die springs provide substantially higher force and energy storage within a given pocket volume compared to round-wire springs, but exact force ratios depend on wire geometry and material.
The live text lists 475 without specifying °C or °F. Standard alloy steel springs are limited to ~80°C (176°F) before experiencing heat relaxation. Operating at 475°C requires superalloy metals like Inconel. The unit must be specified.
Die springs tolerate rapid cyclic loads, but unguided impact or sudden release without adequate preload creates damaging stress spikes that shorten fatigue life.
Sustained static compression under heavy load causes stress relaxation over time, leading to gradual loss of free length and lower initial force.
Cycle life depends on deflection ratio, operating speed, temperature, alignment and environment. Staying within long-life deflection limits yields up to 1 million cycles.
Yes, provided guide clearance is accurate, heat buildup is managed, and stroke frequency does not induce internal spring surge or harmonic resonance.
Guiding is mandatory. Springs with free length to diameter ratios greater than 4:1 require internal guide rods or deep pocket walls to prevent lateral buckling.
Buckling occurs when an unguided long spring is compressed. The middle coils bow laterally, resulting in unequal stress distribution, wall rubbing and early failure.
Side loading creates severe stress concentration on one side of the active coils, leading to localized wear, coil rubbing and premature fatigue cracking.
Series stacking requires an intermediate guide washer and guide rod. Stacking halves total spring rate and doubles total compression stroke for a given load.
No. Used springs experience set and lower force capacity. Combining new and old springs leads to uneven load distribution and plate cocking. Always replace springs in full sets.
Permanent set is irreversible loss of free length caused by over-stressing steel beyond its elastic limit. Settled springs deliver lower operating force.
Fatigue fracture results from cyclic over-deflection, surface damage, coil clashing, internal inclusions, improper heat treatment or corrosion pitting.
Rust creates micro-pits on wire surfaces that act as stress raisers, sharply lowering fatigue resistance and leading to sudden brittle breakage.
Overloading beyond recommended deflection causes rapid set, permanent shortening, coil clashing and early fatigue fracture during operation.
Inspect free length, coating condition, surface cracks or nicks, end face squareness, coil clearance wear, and guide rod/pocket condition.
