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PRODUCT

PRIDE OF QUALITY PARKWON STEEL BALL

Product Introduction

Ceramic Ball

Introduction

Ceramic(Si3N4)

As a method to overcome the disadvantages of the existing high-carbon chrome bearing steel (SUJ) under special environments such as high speed, high temperature and electrolytic corrosion, it is used for electric cars and lightweight bearing.

Parkwon uses blank balls supplied by sintering companies using HIP method approved by clients and has established a Grade 5 mass production system upon the completion of quality validation by a global bearing company.

Process Explanation

Process explanation
Category Ceramic powder
(Silicon nitride powder)		 Blank Ball (sintering) Ball
(Finished product)
#01 #02 #03 #04 #05 #06 #07 #08
Process 3/16” ~ 1/2” 4,762 ~ 12.7mm Mix Molding
(Figuration)		 Manufacture Sintering
(HIP : HOT Isotatic pressing)		 Processing
(Grinding)		 Inspection

Types of Ceramic Balls

Types of ceramic balls
Type Rolling bearing ceramic
Characteristics Purpose of use Application
Si3N4 High strength, non-magnetic, wear resistance, corrosion resistance Bearing for high load / high speed rotation Turbocharger, spindle, motor engine, etc.
ZrO2 High temperature resistance, high strength, wear resistance Bearing for high temperature Parts for furnace, high temperature (gas turbine)
ZrO2 Industrial pump
AI2O3 Dielectric, high strength, wear resistance Bearing for electronic equipment Semiconductor and bio (human skeleton) parts

Quality standard

Blank Ball Material Quality
Blank ball material quality
Item Inspection Method Specification Inspection
Frequency *1, *2
1. Physical
Properties		 Elastic Modulus Bend Resonance Method 298 ~ 318 [GPa] n=1 / Material Intrinsic Value (not routinely measured)
c = 0
Poisson's ratio 0.28 ~ 0.30
Coefficient of Thermal Expansion Optical Interferometry 2.9 ~ 3.2 [x10-6/deg c]
Thermal Conductivity Laser Flash Method 18 ~ 25 [w/mk]
Constituent Phase*3 X-ray Diffraction Method Cu K α No residual alpha phase peak
2. Mechanical
Properties		 Density Archimedes's Method 3.22 ~ 3.26 [Mg/m3] n=5 / Manufacturing lot
c = 0
Hardness Vicker's Method 196, 1N - 30sec, (ASTM F 2094) 1400 ~ 1750 [HV] n=3 / Manufacturing lot
c = 0
Rupture Strength 3-point Bending Test (J|S R1601) Min.735 [MPa] n=20 / Material lot (powder lot)
Toughness |F Method 196, 1N - 30sec, (ASTM F 2094) 6 ~ 8 [MPa·m1/2] n=3 / Manufacturing lot
c = 0
3. Internal Defect *3*4 Metallograph x200 To not have following inside (cross section) of blanks
  1. Inclusions over average diameter of 15um (excluding sintering additive element)
  2. Voids over average diamante of 10um
  3. White or Black Color discoloration : Less than half of Grinding Allowance
 n=5 / Manufacturing lot * In case the shipment qty is 1kp or less, n=3 / Manufacturing lot
c = 0
4. Crack *3 Fluorescent Penetrant Test (Visual inspection under UV lamp after immersion to fluorescent penetrant washing and drying) No Crack One Hundred Percent Inspection
5. Appearance *3 Visual Check / Boundary Sample (Depth of chipping and height of protrusion on boundary sample will be produced by using depth of focus method of metallograph,)
  1. Chipping/dent : Depth of less than 0.15mm (Length and Width will be allowed)
  2. Protrusion : Height of less than 0.20mm (Length and Width will be allowed)
  3. Attachment of foreign particles : will be allowed
  4. Foreign substance on surface : will be allowed
  5. Roughing of surface : Same as chipping/protrusion
  6. Color unevenness : will be allowed
  7. Die Mark : Same as chipping/protrusion
 One Hundred Percent Inspection
6. Dimension Micrometer Equator Band Diameter (Diagonal diameter of equator band to be not subject of specification) Diameter variation 0.15mm (~3/8")
0.20mm (13/32" ~)
n=5 / Manufacturing lot
c = 0
  1. Material Lot
    Silicon Nitride powder lot that can assure uniformity of material characteristic
  2. Manufacturing Lot
    Dispatch lot that can assure uniformity of manufacturing record
  3. Report based on passing status judgement
  4. There are cases discoloration is observed after finishing, even though internal defect of inclusion or pore are not detected. This will be considered to be not a subject of defect.