S705 tool steel 2

[bearingsteel]

I'm having problems with S705 BOHLER tool steel as I can't find anything about the microstructure. Can anybody please help me with this? This steel is quenched and tempered, so it must have small carbides and a clean structure. I didn't find any photo on the web regarding the structure.

 

[TVP]

S705 is roughly equivalent to the ASTM grade M35, which has Cr, Mo, W, Co, & V. There will be a martensitic microstructure with spherical carbides present. Here is an example from a different manufacturer:

http://www.latrobesteel.com/assets/documents/datasheets/Bulletin_101.pdf

 

[metman]

bearingsteel,
You said, "I'm having problems..." Can you be more specific about the problems you are having?

Are you using the following the recommended heat treat process for this AISI M41/UNS T11341 High Speed Tool Steel? Please note they are recommending a triple tempering cycle where the last cycle is stress relief.

Following is the recommended Hardening and tempereing process:

Hardening:
1190 to 1230°C (2174 to 2246°F)
Oil, salt bath (500 to 550°C (932 to 1022°F),
vacuum.
Up per tem pe ra tu re ran ge for parts of simple
sha pe, lo wer for parts of com plex sha -
pe. For cold wor king tools also lo wer tem pera
tu res are of in por tan ce for hig her
tough-ness. Soa king time af ter hea ting up
the who le sec ti on of a work pie ce 80 se -
conds mi ni mum is re qui red for dis sol ving
suf fi cient car bi des.
Ma xi mum soa king time 150 se conds to
avoid de tri ments by over soa king.
In prac ti ce ins te ad of soa king time the time
of ex po su re from pla cing the work pie ce into
the salth bath af ter pre hea ting un til re mo -
ving (in clu ding the sta ges of hea ting to the
spe ci fied sur fa ce tem pe ra tu re and of heating
to the tem pe ra tu re throug hout the
whole sec tion) is used. “see im mer si on
time dia grams”.


Tempering:
Slow hea ting to tem pe ring tem pe ra tu re imme
di ate ly af ter har de ning/time in fur na ce:
1 hour for every 20 mm of work pie ce thick -
ness, but not less than 2 hours/ air coo ling
(mi ni mum hol ding time: 1 hour).

1st tem pe ring and

2 nd tem pe ring to de si red
wor king hard ness.
Aver age ob tai na ble hard ness va lu es are
shown in the tem pe ring chart.

3rd tem pe ring for stress re lie ving,
30 - 50°C (86-122°F) be low hig hest tem pe -
ring tem pe ra tu re.
Ob tai na ble hard ness af ter tem pe ring:
64 - 66 HRC.


Design for RELIABILITY, manufacturability, and maintainability

 

[bearingsteel]

I need some photos of what is allowed and what is not. I don't know if the microstructure is good because i don't have anything to compare to. This is my problem.