Power Transmission Products S684ZZ Bearing 4x9x4mm ABEC-5 440C Roller Stainless Steel Deep Groove Ball Bearings S684Z S684 Z ZZ Ball Bearings

ball bearingWHY 440C STAINLESS steel?Good corrosion resistance to water and many weak chemicalsCorrosion resistance can be improved by passivationGood for temperatures up to 300°CSlightly softer than chrome steel so lower load ratingsWill corrode in salt water or salt spray and poor resistance to acids/alkalisMore expensive than chrome steelWhat is 440C?A martensitic stainless steel. It's composed of these major alloy elements (I don't list the minor elements since they don't play a major role):Carbon: 0.95-1.25% This increases hardenability and wear resistance but decreases toughness in higher amounts.Manganese: 45% This is added to reduce brittleness and improve forgeability hardenability and reducing deformation.Silicon: 30% This is a deoxidizer and improves hot-forming properties.Chromium: 17.00-18.00% Added only to high alloy tool steels this improves hardenability high wear resistance toughness and corrosion resistance.Molybdenum: 50% Improves deep hardening and toughness.These basic elements (along with iron) are a simple combination that works well together and has for many decades.This alloy is technically classified as UNS (Unified Numbering System) S44044. It's also classified as SAE (Society for Automotive Engineers) as 51440C.The American Iron and Steel Institute classifies it as 440C martensitic standard stainless steel. Most modern knifemakers simply call it 440C.

• ball bearing
• Item: S684ZZ; Structure: Deep Groove; Material: 440C Stainless Steel ( prefix "S" )
• Bore Dia (d): 4 mm; Outer Dia (D): 9 mm; Width (B): 4 mm
• Closures: Metal Shielded(ZZ); Lubrication: Grease Magnetic: little; Hardness: 58HRC; Corrosion Resistance: General; Clearance: C0
• Dynamic Load Rating (Cr) (Newtons): 545 ; Static Load Rating (Cor) (Newtons): 182
• Grades: ABEC Grades 5; Ball Qty: 7; Ball Dia (Dw): 1.588 mm; Weight: 1 g; Quantity: 1 Lot = 10 PCS