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Products
We supply full-category shock absorber components, including pistons, stampings, rubber seals, piston rods, springs, and self-developed banding/grooving machines.
Heat Treated Steel Valve Shim
Heat Treated Steel Valve Shim by XIAYI starts as vacuum-quenched SK5 at 580 HV — or smooth SK4 for comfort tuning — with thickness ground to a 0.005 mm window. Sourced from China with material reports in every batch, it turns shim selection into science instead of guesswork.
The Heat Treated Steel Valve Shim is built on SK4 and SK5 high-carbon valve steel — vacuum quenched and tempered, with chemical composition controlled grade by grade. Different steel decides elasticity, fatigue and life; different thickness decides opening pressure and ride. Getting both right is what turns "a piece of shim steel" into a tunable, durable damping component.
SK4 vs SK5: Two Grades, Two Personalities
| Grade | Hardness | Carbon C | Elasticity | Best For |
|---|---|---|---|---|
| SK4 | 500–520 HV | 0.93–0.96% | Medium-high, smooth | Comfort, sedan, standard |
| SK5 | 550–580 HV | 0.98–1.05% | High-rigid, fast | Handling, SUV, EV, tuning |
Composition is deliberate: higher carbon brings rigidity and opening pressure; optimized silicon gives linear rebound and anti-fatigue; manganese adds strength against breakage; low phosphorus and sulfur keep the steel pure — no micro-cracks, longer life.
The Thickness Ladder — Your Tuning Scale
Every 0.01 mm of thickness changes damping by 15–25% — this ladder is the core of shock tuning:
| Thickness | Opening Character | Damping Feel | Typical Use |
|---|---|---|---|
| 0.10 mm | Early, soft response | Ultra-soft, comfort | Secondary shim, low-speed |
| 0.15 mm | Early, smooth | Soft, comfort | Sedan, city driving |
| 0.20 mm | Linear, balanced | Balanced comfort + support | Universal main shim, SUV |
| 0.30 mm | Late, firm | Firm, supportive | EV, handling, heavy load |
| 0.40 mm | Very late, rigid | Stiff, strong support | Commercial, off-road |
| 0.50 mm+ | Ultra late, ultra rigid | Extreme firm | Machinery, heavy-duty |
Material × Thickness: Prescribed Combinations
| Combination | Damping Character | Pain Point Solved |
|---|---|---|
| SK4 + thin (0.10–0.15) | Soft low-speed, good filtering | Fine vibration, motion sickness |
| SK4 + medium (0.20) | Fully linear balanced | City + mixed roads |
| SK5 + medium (0.20–0.30) | Firm support, fast response | High-speed float, body roll |
| SK5 + thick (0.40+) | High damping, strong support | Heavy-load collapse, rough-road failure |
FAQ
Q: Our current shocks are too soft with brake dive. Which change fixes it?
A: That is the classic "too soft material / too thin shim" signature. The standard fix is upgrading to SK5 with a thicker step — typically moving up one rung on the thickness ladder — confirmed against your vehicle weight and oil pressure.
Q: Why do shims from other suppliers keep breaking?
A: Usually impure material or over-hard tempering. Our SK4 line with stable tempering is the anti-breakage choice — SK4 trades a little rigidity for markedly lower break risk.
Q: Can we order SK4 and SK5 in one program?
A: Yes — many customers run SK4 for comfort variants and SK5 for sport/SUV variants from the same tooling, with tight ±0.005 mm thickness tolerance across both grades.
Tell us the ride complaint — get the SK4/SK5 + thickness prescription
Ningbo XiaYi Electromechanical Tech Co., Ltd. matches material grade to thickness with real factory data. Send your damping issue and vehicle type for a material-thickness recommendation.
About XIAYI material transparency: factory material reports — composition, hardness band and thickness tolerance — accompany the SK4/SK5 steel we buy, and the same reports back every recommendation we make, so your tuning decisions rest on measured data.
Send Inquiry
Contact Info
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Address
No.209 Lane 520 Tongning Rd,Qianjiang Street,Jiangbei District, Ningbo City, Zhejiang Province, China
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Get a Tailored Quote for Your Shock Absorber Parts
Why Global Buyers Choose Ningbo Xiayi:
✓ IATF 16949 Certified — Defect rate strictly controlled below 0.1%.
✓ Full-Category Supply — Pistons, rods, springs, stampings & rubber parts.
✓ R&D Support — Custom powder metallurgy formulas & 7-10 day rapid prototyping.
✓ Proven Capacity — 50 million core pistons produced annually for global OEMs.
Ready to start? Complete the form below and our engineering team will respond within 24 hours with a custom recommendation.
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