TSH Technology

TSH-catalogThrough Surface Hardening 
Process using low hardenability steel
Strategic Partner: Inductoheat, Madison Heights, MI – world’s largest producer of induction equipment

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TSH Technology

Breakthrough Technology for Induction Contour Hardening of Complex Geometry Parts
Sprial Bevel
Sprial Bevel2

Spiral Bevel Pinion

Faster, Simpler, Cheaper, More Reliable, Green & Lean Manufacturing/ Materials Technology => Replaces Gas Carburizing

Spiral Bevel
Spiral Bevel

13” Helical Bull Gear

What is TSH Technology?

  • Synergistic combination of controlled low hardenability (LH) advanced steels and superior induction hardening techniques.
  • TSH Technology serves the Automotive, Commercial Vehicle, Agriculture, Mining, Industrial and Railroad Industries as an alternative steel / heat treat technology for case hardening (carburizing, carbonitriding), through hardening and conventional induction hardening of heavy duty alloy steel parts
  • TSH = Through Heating for Surface Hardening, Parts are through heated by low  or medium frequency induction heating and then rapidly quenched resulting in a surface hardened layer profiling the part.
  • Parallel axis gears
  • Differential bevel gears
  • Spiral bevel gears
  • Track bushings
  • Transmission shafts
  • King pins, diff pins, piston pins, ball Joints
  • Leaf and coil springs
  • Journal and differential crosses
  • Camshafts and crankshafts
  • Tillage tools
  • Grinding mill balls
  • Bearings
AoutomotiveAutomotive Journal Cross
Locomotive BearingLocomotive Bearing

TSH Benefits

Cost Effective Alternative Process 
     Uses low cost TSH steels

  • 3-8 times less alloying elements (Mn, Cr, Ni, Mo)
  • Expensive alloy elements (Ni, Cr) are not specified
     Replaces carburizing or conventional induction hardening for many alloy steel parts
  • TSH cycle times 1-5 minutes versus 8-20+hours for carburizing
     Lean and green process allowing individual gear traceability

2.    Superior Metallurgy / Improved Durability
  • Produces fine-grain to ultra-fine grain martensitic structures within the surface  hardened layer
  • Improves surface metallurgy by eliminating grain boundary oxidation or nonmartensitic  surface layer Associated with gas carburizing
  • Heat treated core structure (bainite and pearlite) resulting in a good combination of core ductility  and strength.
  • Develops high magnitude of the desirable compressive surface residual stresses (600-1000 MPa)
  • Significantly improved static and dynamic properties
3.    Simple, Repeatable and Robust Process
  • Parts are through heated or partial heated and then rapidly quenched    
  • Hardened depth is controlled by the steel’s hardenability
  • Limited steel hardenability allows the formation of well defined hardness pattern when hardening complex-geometry parts
  • Uses low or medium induction hardening frequencies (1kHz to 15kHz) reduce equipment capital cost
  • Dramatically reduces probability of overheating edges, tips and corners
  • Improves overall repeatability and robustness. reduces process sensitivity
Carrier PinCarrier Pin – Simultaneous OD & ID Hardening
Pump GearPump Gear Shaft

TSH Case Studies

Case Study: Hypoid Drive Pinion – TSH Process vs Gas Carburized

The conventional heat treat process for hypoid drive pinion is gas carburizing. Conventional induction contour hardening is not practical due to the complex part geometry. The TSH technology makes induction contour hardening of this part possible.


Case Study:  Helical Bull Gear – Induction Hardened by TSH Process

Hypoid Drive PinionInduction contour hardening technology can be used for this 13” helical bull gear to replace gas carburizing. TSH technology is the best contour hardening process for these larger parts.  The TSH process utilizing lower power, low frequency induction heating reduces equipment cost and makes the process more repeatable and robust.  In addition, the core of the gear tooth is heat treated.

Helical Bull Gear

  • Outer Diameter = 330 mm (13”)
  • Number of Teeth = 47
  • Module = 6.8 mm
  • Weight = 13.8 kg (29#)
Helical Gear Helical Gear Chemistry by Stork Climax Research Services
Helical Bull Gear
Helical Bull Gear


Superior Metallurgy => Enhanced Performance

Advanced TSH Steel Technology

Characterized by
  • low or no alloy content
  • reduced tendency for grain growth during heating
  • LH steels control harden depth capability
  • capability to develop high compressive residual stresses
LH SteelTypical LH Steel Chemistries


Meet the Steel Cost Challenge Utilizing TSH Steels

Reduced Alloy

Reduced Alloy  =>  Lower Cost

ERS / Techmash Assumes “Total Application Responsibility” For Your Parts

Part Selection and Evaluation  
  • Customer specifies part
  • TSH feasibility and LH steel selection by ERS/Techmash
  • Cost savings evaluated by ERS and customer
Process Development for Prototype Parts
  • ERS/Techmash supplies LH steel to customer
  • Customer manufactures part from supplied LH steel
  • ERS/Techmash together with Inductoheat inc develop the TSH process and heat treat prototype parts
Prototype part evaluation and testing
  • Customer verifies quality of prototype parts
  • Customer tests prototype parts
Part qualification for production
  • Induction equipment supplied by Inductoheat, Inc
  • Technical support provided by ERS/Techmash and Inductoheat, Inc
  • LH steel produced by North American steel supplier developed by ERS/Techmash

TSH Technology

Contact ERS Engineering to see how you can benefit by utilizing the TSH technology