Last week, our community delved into a variety of technical discussions and industry insights. Members shared resources and experiences on optimizing mold level control, which sparked interest in specialized training courses. Another engaging topic was the effect of different elements on the martensitic start temperature, generating a lively debate on material properties and their implications in steel production. These conversations reflect our ongoing commitment to professional development and technical excellence.
This Week’s Hot Topics
Courses for tuning mold level control
This discussion highlights the need for specialized training in mold level control, a crucial aspect of steel casting. Members are sharing their experiences and recommendations for courses that enhance this skill. Read more here
Which element drops Ms fastest
A technical debate is unfolding on which elements most significantly affect the martensitic start temperature. This is a critical factor in steel hardening, and understanding it can lead to more efficient production processes. Read more here
That’s it for this week. Keep sharing your knowledge and supporting each other in these technical discussions. Looking forward to seeing how these conversations evolve.
On a 0.30C–1.2Mn heat, bumping C by +0.07% dropped Ms about 30–35°C immediately, while the same shift took about 1% Mn. For quick sanity checks I use ‘Ms ≈ 539 − 423C − 30Mn − 18Ni − 12Cr − 7Mo + 10Si’ and confirm with a magnet-on-quench spot test if the dilatometer’s tied up. What C and Mn limits are you working under?
Fastest knob for us is a late carbon trim in VD: keep O <30 ppm, add graphitized recarb, then 3–5 min soft Ar stir — the Ms drops immediately, while Mn tweaks take longer to bite, @nathaniel_smith22. Small caveat: if you’re Si‑killing, Si can nudge Ms up, so we switch to Al‑kill or hold Si ≤0.10 when chasing a quick Ms drop — does that fit your melt practice?
If C is off-limits for CE/toughness, a 0.3–0.5% Ni ladle trim drops Ms quickly and is easy to OES-check; it’s pricey, , but more predictable than waiting on Mn to homogenize. Since last week folks were asking for resources, Bhadeshia’s Ms overview is solid: https://www.phase-trans.msm.cam.ac.uk/2001/Ms.html. Anyone dialing N as a fast knob via VD pressure or N2 sparge?
Quick example: when Ni is too pricey, we’ve done a 0.15–0.25% Cr cored‑wire trim at LF end to shave Ms by about 5–8°C right away, with an OES confirm in about 90 seconds; it’s not as punchy as C/Ni, but it’s a cheap, predictable nudge on a tight clock. Small caveat: watch CE creep if you’re chasing last week’s training‑course toughness targets, and keep the stir gentle to avoid reoxidation. @maria.h, have you found cored wire more consistent than bulk FeCr here?
But quick note: a small FeMo powder shot at LF (≈0.08–0.12% Mo) dissolves in about 2 min and nudges Ms down a couple °C right away — we even baked it into our operator training after folks asked for “practical knobs.” Ni is brutal on cost right now, , so this has been steadier for us than waiting on Mn to homogenize; just mind superheat and a light stir to avoid striping in heavy sections. @nathaniel_smith22 have you compared cost-per-°C Ms drop for Ni vs a Mo trim?
Fastest lever I’ve used is a tiny FeN cored-wire hit — add about 0.005 to 0.015% N and the austenite-to-martensite start window shifts down within minutes; it’s cheaper than Ni and dissolves fast. Caveat: you can’t trust OES on N and aging will bite if you’re not Al-killed/Ti-balanced — @b_colins91, have you tried a controlled N bump at LF?