Provning av ythärdade material tänkta för <br /> transmissionsdetaljer

Sammanfattning

This technical report describes the master thesis in material engineering

called ?Testing of surfaced hardened materials conceivable for gears and

shafts?. The work extents 20 academic points. Land systems Hägglunds

manufactures and sells different kinds of combat vehicles and terrain

vehicles. Since the demands for bigger and stronger vehicles increases all

the time, so are the demands on shafts, gears and other transmission

details. The aim of this master thesis is to find and test some new surfaced

hardened materials. After literature search and discussions and interviews

with some different companies , four new materials were chosen to be tested.

These four material were the tool steel THG2000, PM steels Vanadis 10 and

Vanadis 30, and the maraging steel Vasco Max C300. As reference, two of

Hägglunds current used steels were tested too. These were 2511 for case

hardening and 2244 for induction hardening. To compare the different steels,

tensile strength, bending strength and microhardness were tested. In the

beginning, the materials were to be case hardened or induction hardened.

Hägglunds use these methods today, and all necessary equipment is available.

Later, it was decided that the materials should be nitrated. This will give

a thinner but harder surface. The work was carried out at Testlab at Ltu,

and the tests showed that VascoMax had the highest yield strength and

tensile strength, 2030 resp. 2070 MPa. After that followed THG2000 at 1410

and 1590 MPa, 2244 at 1160 and 1390 MPa, 2511 at 900 and 1170 MPa. The PM

steels behaved brittle and did not show any plasticity. The Vanadis 10 broke

at 1030 MPa and Vanadis 30 at 1210 MPa. In the bending test, load and

deflection were measured. Highest measured load was found in the VascoMax

test. Then, in decreasing order, 2204, THG2000, 2511, Vanadis 10 and Vanadis

30. The exact numbers in these tests may not be as accurate as desirable:

neither VascoMax or 2244 could be forced to fracture. The loads in the

report are those measured when the deflection was too big and the tests were

aborted. My conclusion after these tests are that the steels VascoMax C300

and THG2000 should be very interesting for Hägglunds to continue to work

with. Possible future tasks could be fatigue and torsion tests.