1、AISI 440C Stainless steel ball
Size: 0.35mm- 50.8mm
Grade：G10, G16, G40, G60, G100, G200.
Hardness: HRC56-58,Hartford 440C stainless steel balls are passivated to remove free iron contaminants and facilitate spontaneous formation of a protective passive film.
Magnetic:Martensitic steel, magnetic
Features: high precision, good corrosion resistance, strong rust and wear resistance.
Applications:Bearings,stamping,hydraulic parts, valves, aerospace, seals, refrigeration equipment, high-precision instruments, etc.

2、AISI 420C Stainless steel ball
Size: 0.35mm- 50.8mm
Grade : G10-G1000
Hardness: HRC50-55
Magnetic:Martensitic steel, magnetic,Good anti-rust ability,High hardness,AISI 420 stainless steel balls demonstrate good wear characteristics and hardness. Slightly less hardness and greater corrosion resistance, when compared to 440C.
Features:Commonly known as stainless iron, good corrosion resistance and toughness.
Applications:All kinds of precision machinery, bearings, electrical equipment, household appliances, auto parts, etc.

3、430 stainless steel ball
Diameter: 1MM-50.80MM
Hardness: HRC26
Grade : G10-G1000
Features: low price, poor rust resistance.
Application:hardware, ornaments, accessories, cosmetics, industry, industries with low requirements for antirust performance.Cosmetics agitators, nail polish and eyeliners, heat exchangers, measurement instruments. and valve balls.

4、AISI 304 Stainless steel ball
Size: 0.5mm- 63.5mm
Grade : G80-G500
Hardness: ≤HRC21
Magnetic:Austenitic steel, non-magnetic
Features: strong rust resistance, good corrosion resistance.widely used, good rust proof performance, good surface effect, environmental protection certification.
Applications:Household appliances such as valves, perfume bottles, nail polish, baby bottles, auto parts, air conditioners, electrical appliances, cosmetics, bearing slide, medical equipment, jewelry and many other industries.

5、AISI 316L Stainless steel ball
Size: 1.0mm- 63.5mm
Grade : G80-G500
Hardness: ≤HRC26
Magnetic:Austenitic steel, non-magnetic
Features: the most suitable for industries with high anti-corrosion requirements, and the anti-rust ability is very strong,Excellent resistance to corrosion(apart of chloridric acids),Not hardenable austenitic inox
Applications:AISI 316L stainless steel ball can be used for medical equipment, chemical industry, aviation, aerospace,plastic hardware, perfume bottle,sprayer, valves, nail polish, motor, switch,iron,washing machines, refrigerators,air conditioners,medicinal materials,auto parts, bearings, instrument, bottle.

Product packaging
A) Inner packing: Dry packing or oil packing are provided according to you needs.
B) Outer packing:
1)volatile rust preventive paper + poly bag + iron drum + wooden / iron pallet.
2)25kg poly bag + carton + wooden pallet or wooden box.
3) customized packing.
　

1,Can you provide sample free?
Yes ,we can provide free samples with in 0.5kg.
2,What kind of payment terms you can accept?
We can accept T/T,L/C, Western Union and Paypal.
3,What about your steel ball’s quality?
Checking in the whole manufacturing process &100% inspection before shipment ensure the quality of our products.
4,What’s your packing method?
A) Inner packing: Dry packing or oil packing are provided according to you needs.
B) Outer packing:
1)volatile rust preventive paper + poly bag + iron drum + wooden / iron pallet.
2)25kg poly bag + carton + wooden pallet or wooden box.
3)customized packing.
5,What’s your delivery time?
Within 3-30 days according to your required size and quantity.
6,Is your steel ball competitive?
Yes, We are steel ball manufacture more than 18 years.
　

Production process

Raw Material Inspection
Raw material comes in wire form. This material is first visually inspected for quality and lack of any defects. Diameter is verified and the raw material certificate is reviewed.
Cold Heading
The cold heading machine cuts off a specified length of the wire material into a cylindrical slug. Two hemispherical halves of the heading die then form the slug into a roughly spherical shape. This forging process is performed at room temperature and a slight amount of excess material is used to ensure that the die cavity is completely filled. Cold heading is performed at very high speeds with cycle time averaging about one large ball per second. Smaller balls are headed at rates between two to four balls per second.
Flashing
Excess material that forms around the perimeter of the precision steel ball is removed during the flashing process. The balls are passed numerous times between two grooved cast iron plates removing small amounts of excess material as they roll.
Heat Treatment
Parts are then heat-treated using a quench and temper process. A rotary furnace is employed to ensure that all parts are exposed to the same conditions. After the initial heat treatment, the parts are immersed in an oil reservoir. This rapid cooling (oil quenching) produces martensite, a steel phase which is characterized by high hardness and superior wear properties. Subsequent tempering operations further decrease internal stresses until the final specified hardness range of the bearing is reached.
Grinding
Grinding is performed both before and after heat treatment. Finish Grinding (also known as Hard Grinding) brings the ball closer to its final requirements. The grade of a precision metal ball is a measure of its overall precision; the lower the number, the more precise is the ball. Ball grade encompasses diameter tolerance, roundness (sphericity) and surface roughness - also called surface finish. Precision ball manufacturing is a batch operation. Lot size is determined by the size of the machinery used for the grinding and lapping operations.
Lapping
Lapping is similar to grinding but involves a significantly lower material removal rate. Lapping is performed using two phenolic plates and a very fine abrasive slurry such as diamond dust. This final manufacturing process greatly improves surface roughness. Lapping is required for high precision or super precision ball grades.
Cleaning
A cleaning operation then removes any processing fluids and residual abrasive material from the manufacturing process. Customers requiring more stringent cleanliness requirements, such as those serving micro-electronics, medical or food industries, can take advantage of Hartford Technologies more sophisticated cleaning options.
Visual Inspection
After the primary manufacturing process, every lot of precision steel balls undergoes multiple in-process quality control checks. A visual inspection is performed to check for defects such as rust or dirt.
Roller Gauging
Roller gauging is a 100% sorting process that separates both under-size and over-size precision steel balls. Please check out our separate video on the roller gauging process.
Quality Control
Each lot of precision balls is inspected to ensure grade requirements for diameter tolerance, roundness and surface roughness. During this process, other relevant characteristics such as hardness, and any visual requirements are also evaluated.