AKS produces steel balls(for rolling bearings) that conform to the Japanese Industrial Standard JIS B1501-2009.

This Japanese Industrial Standard specifies requirements for finished steel balls for rolling bearings.

【Quotation】

1	Terms and definitions	The principal terms, quantitative symbols and definitions used in this Standard shall be as follows.
	1.1 Ball size	The designations which is used for the purpose of general identification of a steel ball by dimension.
	1.2 Nominal ball diameter, Dw	The value in which a ball size is expressed by the unit of mm.
	1.3 Single ball diameter,Dws	The distance between two parallel planes tangential to the actual surface of a ball.
	1.4 Mean ball diameter,Dwm	The arithmetic mean of the largest and the smallest of the single distance of a ball.
	1.5 Variation of ball diameter, VDws	The difference between the largest and the smallest of the single diameters of a ball.
	1.6 Surface irregularities and form parameters	The various types of deviation from the perfect spherical ball surface, uniformly or non-uniformly distributed and repeated around the ball surface.
	1.6.1 Deviation from spherical form	The radial distance between the smallest circumscribed sphere and the greatest inscribed sphere, with their centers common to the least squares sphere centre.
	1.6.2 Waviness	The surface irregularities of random or periodical deviation from the ideal spherical form.
	1.6.3 Surface roughnessDwmD	The surface irregularities with relatively small spacings, which usually include irregularities resulting from the method of manufacture being used and/or other influences.
	1.7 Surface defectSSG	Element, irregularity or group elements and irregularities of the real surface, unintentionally or accidentally caused during manufacture, storage, handling or use of the surface.
	1.8 Ball lot	A definite quantity of balls manufactured under conditions presumed uniform and which is considered as an entity.
	1.9 Mean diameter of ball lot, DwmL	The arithmetical mean of the mean diameters of the largest ball and the smallest ball in a ball lot.
	1.10 Variation of ball lot diameter, VDwL	The difference between the mean diameters of the largest ball and the smallest ball in a ball lot.
	1.11 Ball grade, G	A specific combination of dimensions, form, surface roughness and sorting tolerances. Ball grade is indentified by the letter G and a number.
	1.12 Ball gauge, S	The amount by which the mean diameter of ball lot should differ from the nominal ball diameter, this amount being one of an established series.
	1.13 Deviation of a ball lot, ΔS from ball gauge	The difference between the mean diameter of a ball lot and the sum of the nominal ball diameter and the ball gauge.
	1.14 Ball subgauge	The amount of an established series of amounts,　which is the nearest to the actual deviation from the ball gauge of a ball lot.
	1.15 Hardness	Measure of resistance to penetration as determined by a specific test method.
2	Requirements
	2.1 Ball size	The preferred nominal ball diameters are given in Attached Table 1.
	2.2 Accuracy of Form and Surface Roughness	The ball diameter variation, sphericity and surface roughness of the steel balls shall comply with Attached Table 2.
	2.3 Sorting Accuracy	The lot diameter variation, steel balls shall comply with Attached Table 2.
	2.4 Hardness	The hardness values of the steel balls shall comply with Attached Table 3.
3	Material	The material of the steel balls shall comply with JIS G 4805.
4	Measuring methods
	4.1 Mean Diameter of a Ball and Ball Diameter Variation	The diameter necessary for determining the mean diameter of a ball and the ball diameter variation shall be measured with the ball placed between the horizontal plane and the stylus applied vertical to it from different directions. The mean diameter of a ball shall be obtained in the form of the arithmetic mean of the largest and smallest actual single diameters, and the ball diameter variation shall be obtained in the form of the difference between the largest and smallest actual single diameters. In this case, the measuring force shall be not more than 3 N {306 gf}. The mean diameter of a ball shall be corrected taking into account the elastic approach value due to the measuring force and also, as s rule, the elastic approach value due to the mass of the steel ball. accordance with JIS B 1501 appendix A.
	4.2 Deviation from spherical form	The method of evaluating the deviation from spherical form of a steel ball shall be in accordance with JIS B 1501 appendix A.
	4.3 Waviness	"Waviness is recommended to be evaluated as velocity amplitude. Waviness components on the surface of a ball are usually measured with a waviness-meter using a filter."
	4.4 Surface roughness	"For the surface roughness, measure the roughness around the equators of the steel ball with the instrument specified in JIS B 0651, as a rule, and take the center line mean roughness."
	4.5 Variation of ball lot diameter	"For the variation of ball lot diameter, take the difference between the mean diameter of the largest ball and that of the smallest ball in a lot."
	4.6 Hardness	"The hardness of steel balls of 3mm or smaller shall be measured in accordance with JIS Z 2244. The hardness of steel balls larger than 3mm shall be measured in accordance with JIS Z 2245."
5	Inspection	"The inspection of the steel ball shall be made according to clause 4, and its results shall be satisfy clause 2. "
6	Designation	"The steel ball shall be designated by the name, ball sizes, ball gauge and ball grade. Example 1: Steel balls for rolling bearings 3 mm +3μm G10 Example 2: Steel balls for rolling bearings 3/8 +4μm G40"
7	Packaging and Marking
	7.1Packaging	"The steel balls shall be given anticorrosive treatment by applying oils, fats or others, and packed in suitable containers."
	7.2Marking	"Each container shall be marked with the following items on its surface: （1）Name　（2）Ball size　（3）Ball gauge　（4）Ball grade　（5）Quantity （6）Manufacture'ｓ name or its abbreviation （7）Year and month of manufacture or its abbreviation"

Applicable Standards:	JIS B 0651 JIS G 4805 JIS Z 2244 JIS Z 2245 JIS Z 1501	JIS B 0651−Instruments for the Measurement of Surface Roughness by the Stylus Method JIS G 4805−High Carbon Chromium Bearing Steels JIS Z 2244−Method of Vickers hardness Test JIS Z 2245−Method of Rockwell and Rockwell Superficial Hardness Test JIS Z1501 appendix A-Method of evaluating deviation from spherical form
Corresponding International Standards:	ISO 3290-1	Rolling bearings−Bearing parts−Balls for rolling bearings Rolling
Reference Standard:	JIS B 1511	JIS B 1511−General Code for Rolling Bearings

AKS produces steel balls（for rolling bearings）that conform to the International Standard ISO3290-1.

Table 1 Recommended size of ball

Ball size		Nominal ball diameter Dw （mm）	Ball size		Nominal ball diameter Dw （mm）	Ball size		Nominal ball diameter Dw （mm）	Ball size		Nominal ball diameter Dw （mm）
mm	inch		mm	inch		mm	inch		mm	inch
0.3mm		0.3		17/64	6.74688	18mm		18		1　9/16	39.6875
	1/64	0.39688	7mm		7		23/32	18.25625	40mm		40
0.4mm		0.4		9/32	7.14375	19mm		19		1　5/8	41.275
0.5mm		0.5	7.5mm		7.5		3/4	19.05		1　11/16	42.8625
	0.02	0.508		19/64	7.54062		25/32	19.84375		1　3/4	44.45
0.6mm		0.6		5/16	7.9375	20mm		20	45mm		45
	0.025	0.635	8mm		8	20.5mm		20.5		1 13/16	46.0375
0.68mm		0.68		21/64	8.33438		13/16	20.6375		1　7/8	47.625
0.7mm		0.7	8.5mm		8.5	21mm		21		1 15/16	49.2125
	1/32	0.79375		11/32	8.73125		27/32	21.43125	50mm		50
0.8mm		0.8	9mm		9	22mm		22		2	50.8
1mm		1		23/64	9.12812		7/8	22.225		2　1/8	53.975
	3/64	1.19062	9.5mm		9.5	22.5mm		22.5	55mm		55
1.2mm		1.2		03/8	9.525	23mm		23		2　1/4	57.15
1.5mm		1.5		25/64	9.92188		29/32	23.01875	60mm		60
	1/16	1.5875	10mm		10		15/16	23.8125		2　3/8	60.325
	5/64	1.98438		13/32	10.31875	24mm		24		2　1/2	63.5
2mm		2	10.5mm		10.5		31/32	24.60625	65mm		65
	3/32	2.38125	11mm		11	25mm		25		2　5/8	66.675
2.5mm		2.5		7/16	11.1125		1	25.4		2　3/4	69.85
	7/64	2.77812	11.5mm		11.5	26mm		26	70mm		70
3mm		3		29/64	11.50938		1　1/32	26.19375		2　7/8	73.025
	1/8	3.175		15/32	11.90625		1　1/16	26.9875	75mm		75
3.5mm		3.5	12mm		12	28mm		28		3	76.2
	9/64	3.57188		31/64	12.30312		1　1/8	28.575		3　1/8	79.375
	5/32	3.96875	12.5mm		12.5	30mm		30	80mm		80
4mm		4		1/2	12.7		1　3/16	30.1625		3　1/4	82.55
	11/64	4.36562	13mm		13		1　1/4	31.75	85mm		85
4.5mm		4.5		17/32	13.49375	32mm		32		3　3/8	85.725
	3/16	4.7625	14mm		14	33mm		33		3　1/2	88.9
5mm		5		9/16	14.2875		1　5/16	33.3375	90mm		90
	13/64	5.15938	15mm		15	34mm		34		3　5/8	92.075
5.5mm		5.5		19/32	15.08125		1　3/8	34.925	95mm		95
	7/32	5.55625		5/8	15.875	35mm		35		3　3/4	95.25
	15/64	5.95312	16mm		16	36mm		36		3　7/8	98.425
6mm		6		21/32	16.66875		1　7/16	36.5125	100mm		100
	1/4	6.35	17mm		17	38mm		38		4	101.6
6.5mm		6.5		11/16	17.4625		1　1/2	38.1		4　1/8	104.775

Remarks Marks of the nominal ball diameter conform to ISO3290.

Table 2 Form and surface roughness of ball grades,
and sorting accuracy

Grade	Form and surface roughness			Sorting accuracy
	Variation of ball diameter VDWS （Max. ）	Deviation from spherical form （Max. ）	Surface roughness Ra （Max. ）	Variation of ball lot diameter VDWL （Max. ）
G3	0.08	0.08	0.010	0.13
G5	0.13	0.13	0.014	0.25
G10	0.25	0.25	0.020	0.5
G16	0.4	0.4	0.025	0.8
G20	0.5	0.5	0.032	1
G24	0.6	0.6	0.040	1.2
G28	0.7	0.7	0.050	1.4
G40	1	1	0.060	2
G60	1.5	1.5	0.080	3
G100	2.5	2.5	0.100	5
G200	5	5	0.150	10

Table 3 Hardness

Ball size	Hardness
	HV	HRC
0.3 〜 3mm	772〜900	（63〜67）
1/8 〜 30mm	-	62〜67
1　3/16 〜 4　1/8	-	61〜67

Remarks　The values in parentheses indicate converted values for reference.