XSTEELIA™ Catalyst for Steel Innovation
Steel for Cold Heading (CH) / Bolts

NIPPON STEEL's steel for cold heading (CH) / bolts

Even before NIPPON STEEL were integrated into NSSMC in 2012, each company positioned steel for cold heading as an important business field and accelerated development of this product line. Our specific product development over years included the addition of a wide variety of customized features, such as ingeniously designed chemical compositions, to conventional steel products based on official industrial standards, and the commercialization of many proprietary steel products. We are ready to offer customers fine-tuned services that will satisfy their processing conditions and product design requirements.
The segment of steel for high strength bolts, which we are now introducing, is one of the major categories of steel for cold forging. Typically, our wire rods will be drawn into wire in customers’ secondary processing and then forged to make finished products. We will continue to meet the needs of customers by a combination of our abundant product variations, which have been broadened after the integration of the two steel makers, and our expansion of global secondary processing networks.

Steel products which contribute to "higher strengths"

Customer satisfaction

  • High-strength, high-quality bolts developed through proprietary chemical composition designs

ADSseries

MBseries

Steel products which contribute to "process elimination"

Customer satisfaction

  • Cost reductions, energy-saving, and reductions in equipment investment achieved through process elimination

DSwire rods / DLwire rods
New soft wire rods that will soften "after rolling"

ECwire rods
New soft wire rods that will soften "after annealing"

NHF™
High-strength, untempered wire rods

Steel products which contribute to "higher strengths "

A product menu can be selected to meet all the customer's satisfaction, product requirements, and manufacturing needs

High-strength steel having excellent delayed fracture resistance

ADS™series [Processing requirements: Phosphorus-free coating recommended]

[Processing requirements: Phosphorus-free coating recommended]

Ease of
heat treatment		 Strength Application NIPPON STEEL code Typical chemical composition (%)
Base C Si Mn P S Cr Mo others
◎ ○
-12T		 Flange bolts
Hexagon head bolts
Connecting rod bolts
Cylinder bolts
Various bolts for automobile applications
Bolts for civil engineering and buildings		 ADS 1 0.33
-0.38		 0.15
-0.35		 0.60
-0.85		 0.015
or less		 0.010
or less		 0.90
-1.20		 0.20
-0.30		 -
2 0.33
-0.38		 0.15
-0.35		 0.25
-0.45		 0.010
or less		 0.012
or less		 1.10
-1.30		 0.35
-0.45		 Added

MB™series [Processing requirements: Bolt heat treatment conditions specified, phosphorus-free coating recommended]

[Processing requirements: Bolt heat treatment conditions specified, phosphorus-free coating recommended]

Ease of
heat treatment		 Strength Application NIPPON STEEL code Typical chemical composition (%)
Base C Si Mn P S Cr Mo others
○
(high-temperature quenching)		 ◎
-14T		 Flange bolts
Hexagon head bolts
Connecting rod bolts
Cylinder bolts
Various bolts for automobile applications
Bolts for civil engineering and buildings		 MB 12 0.35
-0.40		 0.15
or less		 0.55
-0.75		 0.015
or less		 0.010
or less		 1.10
-1.30		 0.15
-0.35		 Added
14 0.38
-0.42		 0.1
or less		 0.40
-0.60		 0.010
or less		 0.010
or less		 1.20
-1.40		 0.60
-0.80		 Added
*MB14: A brand name is Super High-Tension Bolt™

Steel products which contribute to "process elimination"

DS wire rods / DL wire rods New soft wire rods that will soften "after rolling"

New soft wire rods that will soften "after rolling"

Fabrication method (facility) DS(Direct Softing)、DL(Direct Low temperature annealing)
Applications Bolts, nuts, pins, piston rods, etc.
Manufacturing process

NIPPON STEEL Secondary processing Forging Supplied to customers Conventional steel Rolling Annealing Wire drawing Forging Finished product / Our newly developed steel Rolling Controlled rolling Controlled cooling Eliminated Wire drawing Forging Finished product Reasons behind customer satisfaction By controlled rolling (in-line softening treatment), these wire rods will be softened to the level of their counterpart conventional wire rods after annealing (*) *Conventional annealing LA: low temperature annealing, RA: regular annealing

Customer satisfaction

Low cost

Possible elimination of the annealing process before secondary wire drawing at the customer's plant

Customer satisfaction

Low cost

Longer life of the drawing dies in secondary processing (*depending on the processing conditions)

EC wire rods New soft wire rods that will soften "after annealing"

New soft wire rods that will soften "after annealing"

Fabrication method (facility) EC｛EDC（Easy Drawing Conveyor）＋Controlled Rolling｝
Applications All applications such as bolts, nuts, pins, and piston rods
Manufacturing process

NIPPON STEEL Secondary processing Forging Supplied to customers Conventional steel Rolling Rough wire drawing Annealing + Wire drawing Forging Finished product / Our newly developed steel Rolling Controlled rolling Controlled cooling Eliminated Annealing + Wire drawing Forging Finished product Reasons behind customer satisfaction By controlled rolling (in-line softening treatment), the annealed microstructure will be made homogeneous and refined, resulting in reduced hardness.

Customer satisfaction

Low cost

Possible elimination of the rough wire drawing process

Customer satisfaction

Higher quality

Longer life of the drawing dies due to the reduced hardness before forging (*depending on the processing conditions)

NHF™ High-strength untempered wire rods (NHF)

High-strength untempered wire rods (NHF)

Fabrication method (facility) Steel chemical composition design + EDC (easy drawing conveyor)
Applications 7T, 8T strengths for hexagon head bolts, flange bolts, etc., 10T, 10.9 strengths for stud bolts, U-bolts, etc.
Manufacturing process

NIPPON STEEL Secondary processing Forging Supplied to customers Conventional steel Rolling Annealing Wire drawing Cold forging Quenching and tempering Bluing Finished product / Our newly developed steel Controlled rolling Eliminated Wire drawing Cold forging Eliminated Bluing Finished product Reasons behind customer satisfaction By steel chemical composition designs + EDC technology, the wire rods can be drawn with its surface reduction ratio controlled, resulting in the tensile strength of a cold-forged product equivalent to its counterpart that has been quenched / tempered

Customer satisfaction

Low cost and high quality

Both high strength and the elimination of annealing and quenching / tempering can be achieved at the same time

Customer satisfaction

High quality

Even long bolts can be produced with reduced distortion