Five steel families, one appliance: electrical steel for the motor core that runs for 15 years, spring steel for the valve plate that seats to 0.02 mm flatness, stainless for the hinge that never rusts, and low carbon for the shell you see every day.
A refrigerator compressor runs continuously for 10–15 years. Its motor core must waste as little energy as possible. Its valve plate must seal refrigerant at 0.02 mm flatness through billions of cycles. Its door hinge must survive 30,000 open-close cycles without rust. Its shell must be deep-drawn and painted to a cosmetic finish. No single steel does all of that. The five families below are how appliance engineers match material to function.
Silicon steel (0.5–3.0% Si) with controlled grain structure for high magnetic permeability and low core loss. 50WW470 guarantees ≤4.70 W/kg at 50 Hz/1.5 T; 35WW300 drops to ≤3.00 W/kg for inverter compressors and high-efficiency washers. The core loss number directly determines the appliance's energy efficiency class and electricity consumption over 15 years.
Choose electrical steel for every motor core and stator lamination.C 0.62–0.73% with manganese for hardenability. Compressor valve plates run 0.15–0.30 mm thick, hardened to 45–50 HRC, with flatness ≤0.02 mm. The plate flexes open and closed billions of times; fatigue resistance and flatness are the difference between a quiet, efficient compressor and a noisy, leaking one.
Choose 65Mn/C67S for valve plates, reed valves and compressor springs.C ≤0.15%, Cr 16–18%, Ni 6–8%. Austenitic stainless that work-hardens during stamping and forming, delivering the spring-back a door hinge needs to return to position and a gasket clip needs to hold the seal. Corrosion resistance handles refrigerator condensation and microwave steam without rust staining the visible surface.
Choose SUS301 for every hinge, clip and spring in moist or visible locations.C ≤0.12%, low carbon cold-rolled strip at 0.4–0.8 mm. SPCC provides the formability for deep-drawn refrigerator and washing machine shells and the surface quality for pre-painted or powder-coated cosmetic finishes. SPCD steps up the ductility for deeper draws and more complex geometry. SPHC hot-rolled pickled strip handles chassis structural frames.
Choose SPCC/SPCD for shells, panels and cosmetic structural parts.Indicative values from production appliance programs; the final spec is agreed at RFQ against your component drawing, appliance class and governing standard.
| Component | Steel grade | Thickness | Key parameter |
|---|---|---|---|
| Compressor motor core | 50WW470 | 0.50 mm | Core loss ≤4.70 W/kg (50 Hz, 1.5 T) |
| High-efficiency motor core | 35WW300 | 0.35 mm | Core loss ≤3.00 W/kg (50 Hz, 1.5 T) |
| Compressor valve plate | 65Mn / C67S | 0.15 – 0.30 mm | HRC 45–50, flatness ≤0.02 mm |
| AC compressor vane | GCr15 | 2.0 – 4.0 mm | HRC 58–62, wear-resistant |
| Door hinge / gasket clip | SUS301 | 0.4 – 1.2 mm | Work-hardened, corrosion-resistant |
| Refrigerator / washer shell | SPCC / SPCD | 0.4 – 0.8 mm | Deep-drawable, cosmetic surface |
| Chassis structural frame | SPHC | 1.5 – 3.0 mm | Pickled & oiled, weldable |
| Washer motor core | 50WW470 | 0.50 mm | Core loss ≤4.70 W/kg, punchable |
Core loss values are guaranteed per coil and reported on the MTC. Valve plate flatness and hardness are confirmed per production lot. For energy-label-driven programs, specify the core loss grade at RFQ — the difference between 50WW470 and 35WW300 can change the appliance's energy efficiency class.
All grades supplied with confirmed mechanicals and MTC per coil. Choose by component function, appliance energy class and environmental exposure.
| Component type | Primary grade | Alternative grade | Selection criterion |
|---|---|---|---|
| Standard compressor motor | 50WW470 | 50WW600 | Energy efficiency class vs. material cost |
| Inverter / high-efficiency motor | 35WW300 | 35WW250 | Core loss target for energy label |
| Compressor valve plate | 65Mn | C67S (EN) | Fatigue life + flatness ≤0.02 mm |
| Compressor reed valve / spring | C67S | 70Si2CrA | Higher strength for heavy-duty compressors |
| AC rotary compressor vane | GCr15 | SKH-51 (HSS) | Wear resistance at HRC 58–62 |
| Refrigerator door hinge | SUS301 | SUS304 | Spring-back + corrosion resistance |
| Door gasket clip / seal retainer | SUS301 | SUS430 | Formability + holding force |
| Microwave door hinge | SUS301 | SPCC (zinc-plated) | Temperature + corrosion environment |
| Refrigerator outer shell | SPCC | SPCD | Draw depth + cosmetic paint surface |
| Washing machine drum / tub | SPCD | SPCE | Deep drawability for cylindrical geometry |
| Chassis / base frame | SPHC | SPHD | Load-bearing + weldability |
Grade selection for motor cores is driven by the appliance's energy efficiency label — confirm the target core loss and frequency (50/60 Hz) at RFQ. Valve plate and vane grades are driven by fatigue and wear requirements. Shell grades are driven by draw depth and surface finish requirements for painting.
These are the failure modes that show up in appliance production, in the order appliance engineers care about them.
A valve plate that is not flat to ≤0.02 mm cannot seat perfectly against the valve seat, allowing refrigerant to leak and reducing compressor efficiency. Fix: 65Mn/C67S strip supplied with controlled flatness, hardened and tempered in a way that does not introduce distortion, and surface-ground or lapped to the final flatness. We confirm incoming flatness per coil.
A motor core stamped from a higher core-loss grade runs hotter and draws more current, potentially failing the appliance energy label test. Fix: specify the exact electrical steel grade (50WW470 vs. 35WW300) at RFQ, and confirm the core loss guarantee on the MTC per coil. We can also supply semi-processed electrical steel where the customer's stress-relief anneal finalizes the magnetic properties.
A door hinge made from a non-work-hardening stainless (like SUS430) loses its spring-back over thousands of open-close cycles and the door sags. Fix: SUS301 austenitic stainless, which work-hardens during forming and retains its spring-back through 30,000+ cycles. We confirm the strip's hardness and spring-back properties per coil and can supply trial coils for hinge life testing.
A refrigerator shell that cracks at the draw radius during stamping causes scrap and line downtime. Fix: SPCC or SPCD in the correct temper (skin-passed or fully annealed) with confirmed elongation and plastic strain ratio (r-value). We confirm mechanicals per coil and can supply trial coils for draw testing before production commitment. For deep cylindrical parts like washer drums, SPCD or SPCE is specified over SPCC.
Home appliance production draws on multiple steel families. Match your component below and confirm at RFQ.
50WW470 / 35WW300 non-oriented electrical steel for compressor and washer motor cores with guaranteed core loss. Electrical steel family →
65Mn / C67S spring steel for compressor valve plates, reed valves and弹片 at HRC 45–50 with controlled flatness. Spring steel family →
SUS301 austenitic stainless for door hinges, gasket clips and microwave door components with work-hardened spring-back. Stainless steel family →
SPCC / SPCD low carbon cold-rolled strip for refrigerator and washing machine shells, panels and cosmetic structural parts. Cold-rolled family →
A typical 1/6 HP refrigerator compressor suction valve plate, described the way it runs.
The valve plate is a 38 × 24 mm rectangular reed, 0.20 mm thick, with a 4 mm mounting hole at one end and a tapered free end that seats against the valve seat. The drawing calls 65Mn spring steel strip, 0.20 mm, hardened and tempered to 46–48 HRC, flatness ≤0.02 mm across the full length, surface finish Ra ≤0.4 μm. The strip arrives slit to 40 mm width, is blanked to the reed profile, then deburred, stress-relieved, and inspected for flatness on a granite surface plate with a dial indicator. Every plate is then leak-tested against the valve seat at 0.5 MPa refrigerant pressure — any plate that leaks more than the specified rate is scrapped.
The flatness check is the moment of truth. A plate that is 0.03 mm out of flat will leak at the seat, reducing compressor cooling capacity by 3–5% and increasing energy consumption. That flatness is inherited from the strip — its incoming flatness, its hardness uniformity, and its surface condition. If the strip has hardness scatter across the width, the blanking and stress-relief will introduce distortion that no amount of lapping can fix. Our job is to make the 65Mn strip's hardness, flatness and surface so repeatable that the valve plate line's variables (blanking, deburring, stress-relief) are the only variables left.
The same compressor uses a 50WW470 motor core stamped from 0.50 mm electrical steel, with core loss ≤4.70 W/kg guaranteed on the MTC. The core loss determines how much heat the motor generates during 15 years of continuous operation — a 0.5 W/kg difference between grades can add 3–5 W of continuous heat load in a 200 W compressor, affecting both energy efficiency and compressor cooling. We confirm the core loss per coil and can supply 35WW300 for inverter-driven compressors where the energy label demands ≤3.00 W/kg.
If your appliance program needs electrical steel for motor cores, 65Mn for valve plates, SUS301 for hinges, or SPCC for shells, send the component drawing and we confirm grade, key parameters and a trial-coil plan. Our slitting and processing services cover exact-width coils, cut-to-length sheets and edge conditioning for stamping or deep drawing.
Related reading: how core loss grades like 50WW470 and 35WW300 affect motor efficiency, and how spheroidizing annealing prepares 65Mn strip for hardening and flatness control. For procurement context, see our precision steel strip buyer's handbook.
These grade families share material, processing or application territory with the topic on this page.
50WW470 / 35WW300 non-oriented grades with guaranteed core loss for compressor and appliance motors.
65Mn / C67S / 50CrV4 grades with high elastic limit and fatigue resistance for compressor components.
SPCC / SPCD / SPCE grades with deep-drawability and cosmetic surface for refrigerator and washer shells.
Send component drawing, thickness × width, key parameter (core loss, HRC, flatness), quantity and destination port. Our engineers reply within one working day with grade match and a trial-coil option.