Heat transfer at surface contacts in preheating and heat treatment processes (“Surface Contacts II”)

Indus­tri­al Coll­ec­ti­ve Rese­arch (IGF), 1 July 2021 – 31 Decem­ber 2023

Project description

Sur­face cont­acts bet­ween solids occur at num­e­rous points in ther­mo-pro­ces­sing. Sur­face cont­acts indu­ce an addi­tio­nal ther­mal resis­tance due to non-ide­al cont­act of the solids. The ther­mal cont­act resis­tance depends on various factors:

  • the nor­mal force or the nor­mal stress on the cont­act surface
  • the micro-hard­ness of the surface
  • the ther­mal con­duc­ti­vi­ty of the solids
  • the ther­mal con­duc­ti­vi­ty of the flu­id in the inters­ti­ti­al space
  • the tem­pe­ra­tu­re

Tem­pe­ra­tu­re dis­tri­bu­ti­on at a sur­face contact

Published stu­dies on heat trans­fer bet­ween the sur­faces in cont­act are available for low tem­pe­ra­tures < 100 °C and low cont­act pres­su­res, and in a tem­pe­ra­tu­re ran­ge up to 1250 °C for cont­act pres­su­res abo­ve the yield stress.
In the cur­rent pro­ject, an exis­ting test rig is fur­ther deve­lo­ped for inves­ti­ga­ting the tem­pe­ra­tu­re ran­ge rele­vant to ther­mo-pro­ces­sing at low cont­act stres­ses. The test rig will be used to mea­su­re the ther­mal resis­tance bet­ween sur­face cont­acts. During the mea­su­re­ments, the tem­pe­ra­tu­re, the nor­mal force, and the atmo­sphe­ric com­po­si­ti­ons can be set as para­me­ters. The inves­ti­ga­ti­ons include dif­fe­rent mate­ri­al pai­rings con­sis­ting of steels, alu­mi­ni­um or cop­per alloys as well as cera­mics. The results can be used to descri­be ther­mal cont­act resis­tances more accu­ra­te­ly and to model heat trans­fer in ther­mo-pro­ces­ses more precisely.

Ope­ra­tors of ther­mo-pro­ces­sing plants thus obtain the oppor­tu­ni­ty for more pre­cise pro­cess con­trol of their heat tre­at­ment and hea­ting ope­ra­ti­ons. Plant manu­fac­tu­r­ers can uti­li­ze the models for the design of their plants. Sup­pli­ers of fur­nace manu­fac­tu­r­ers such as engi­nee­ring com­pa­nies for pro­cess model deve­lo­p­ment and/or auto­ma­ti­on tech­no­lo­gy recei­ve addi­tio­nal para­me­ters for inte­gra­ti­on into their pro­cess models that are used to increase the ener­gy and resour­ce effi­ci­en­cy of the plants. All the­se com­pa­nies can thus increase the qua­li­ty of their products.

Project goals

  • Deve­lo­p­ment of a method for mea­su­ring cont­act ther­mal resistances 
    • at sam­ple tem­pe­ra­tures up to 1250 °C
    • at cont­act stres­ses bet­ween 0,1 MPa and 25 MPa
    • in various ambi­ent atmo­sphe­res, inclu­ding pure hydrogen
  • Reduc­tion of the rela­ti­ve mea­su­re­ment error (com­pared to the pre­vious pro­ject) to a maxi­mum of 10 %
  • Inves­ti­ga­ti­on of new mate­ri­al combinations
  • (Fur­ther) deve­lo­p­ment of models for the cal­cu­la­ti­on of tem­pe­ra­tu­re distributions 
    • in steel, alu­mi­ni­um, and/or cop­per coils in heat tre­at­ment furnaces
    • in steel slabs in wal­king beam furnaces
    • in steel lad­les loa­ded with mol­ten metal
  • (Fur­ther) deve­lo­p­ment of a semi-empi­ri­cal model for the ana­ly­ti­cal cal­cu­la­ti­on of cont­act ther­mal resistances

Project participants


Jan Menz­ler, M.Sc.

+49 241 80–25944



The pro­ject (pro­ject no. 21803 N) was sub­mit­ted with the sup­port of the Rese­arch Asso­cia­ti­on of Indus­tri­al Fur­nace Manu­fac­tu­r­ers (FOGI) via the For­schungs­ku­ra­to­ri­um Maschi­nen­bau e.V. (FKM). It is fun­ded via the Ger­man Fede­ra­ti­on of Indus­tri­al Rese­arch Asso­cia­ti­ons „Otto von Gue­ri­cke“ (AiF) in the pro­gram for Indus­tri­al Coll­ec­ti­ve Rese­arch (IGF), initia­ted by the Fede­ral Minis­try for Eco­no­mic Affairs and Cli­ma­te Action due to a reso­lu­ti­on of the Ger­man Bundestag.