What Phases is
Phases runs real metallurgical solvers from a plain-language conversation, covering heat treatment, CCT diagrams, resistance spot welding and virtual Gleeble testing.
The problem it solves#
You want to know what microstructure comes out of a particular cooling schedule, where the transformation curves sit for a candidate grade, or how large a weld nugget forms at a given current. Normally that means a solver license, a mesh, an input deck and half a day of setup before you learn anything.
Phases removes the setup. You describe the experiment in plain language. The agent resolves the material, configures the matching numerical solver, runs it, streams progress back, and attaches the plots, diagrams and stored files to the conversation.
These are real solvers#
This matters more than anything else on this page, so it is worth being blunt about it.
Phases covers four simulation domains: heat treatment and phase transformation, CCT diagram generation, resistance spot welding (RSW), and virtual Gleeble thermomechanical testing. Each one runs a real numerical solver on the server — these are not language-model approximations of physics.
The language model's job is narrow: understand what you asked for, pick the right tool, fill in its parameters, and report back what the tool actually returned. It is instructed never to claim a simulation ran, a diagram was produced, or a file was saved unless the corresponding tool was called and returned a result. Numbers in the reply come out of the solver, not out of the model.
That boundary is also why Phases refuses some questions. It will not tell you a weld preheat requirement, a toughness value, a quench-cracking risk, a solute retention or precipitation outcome, or an age-hardening response from composition and phase fractions alone. Those need calculations or test data the product does not have.
Four simulators#
| Simulator | The question it answers | What comes back |
|---|---|---|
| Heat Treatment Simulator (HT Sim) | What phases and hardness result from this temperature-versus-time schedule? | Fractions of ferrite, pearlite, bainite, martensite and austenite over time, plus dilatation and hardness histories, and a phase-fractions plot |
| CCT/TTT Diagram Generator (CCT) | At which cooling rates does each transformation start and finish? | One diagram built by running the requested cooling rates — 0.1, 1, 10, 50 and 100 °C/s unless you say otherwise |
| RSW Simulator | How large a nugget forms at this welding current, electrode force, weld time and plate stack? | An interactive gallery of result plots including an animated nugget-evolution figure, plus a summary with the peak temperature reached |
| Virtual Gleeble Simulator (V-Gleeble) | How does this material respond to a controlled thermomechanical cycle? | Results for one of eight test modes: CCT dilatometry, hot tensile, hot compression, weld HAZ, isothermal, Satoh, hot stamping and custom |
Two honest caveats belong right here rather than three pages later.
TTT (isothermal) diagrams are not implemented. Asking for one returns an explicit "TTT transformation diagrams are not implemented yet" rather than a guess. Only continuous-cooling diagrams run.
RSW is limited to the grades that have validated bulk electrical, thermal and mechanical properties: DC01, DC03, DC04, DC05, DC06, HC260LA, HC300LA, HC340LA, HC380LA, HC420LA, DP450, DP500, DP600, DP780, 20MnB5, 22MnB5, 20MnB8, 25MnB5, 29MnB7 and EN13261. Other grades are refused, not approximated. See what each simulator supports.
A fifth entry, Spot Weld Tester (SWT), appears in the simulator strip marked "Soon". It is scaffolding and runs nothing.
Each simulator has its own page: Heat treatment, CCT and TTT, Resistance spot welding and Virtual Gleeble.
Materials#
The built-in catalog includes deep-drawing grades (DC01–DC06), HSLA grades (HC260LA–HC420LA), dual-phase grades (DP450–DP780), boron press-hardening steels (20MnB5, 20MnB8, 22MnB5, 25MnB5, 29MnB7) and the railway axle reference steel EN13261. Ask what is available and the agent queries the live catalog rather than reciting a list from memory.
You can also supply your own chemistry. Phases identifies the closest named grade, tells you which one it is, and asks you to confirm before it creates anything — because a chemistry you typed is not a calibrated material. That gate is explained in Using your own chemistry.
Workspaces can save custom grades to a shared library. See Workspace materials and The material catalog.
What a session looks like#
You state a grade and process conditions in prose. The agent replies with an editable parameter card summarizing what it understood. You adjust anything you disagree with and press the run button. The simulation runs, streaming live progress. Results arrive as plots and diagrams attached to the conversation, stored under a numbered run you can return to later.
There is no default material anywhere in that flow. "Run a simulation" or "surprise me" gets a question back, never a run. That is deliberate, and How the conversation works explains why.
Who it is for#
Metallurgists and process engineers who know steel and do not want to learn a simulation package to answer a bounded question. You need to know what you are asking; you do not need to know how the solver is wired.
You can try it without an account. Guest sessions are limited — 5 messages per 24 hours by default — and guests get only the chat itself, without the run browser, materials pages or history. Signing in adds persistent chat history, saved runs and artifact storage. See Guests and limits.
What Phases does not do#
- It does not replace review. Results are numerical simulations and, like any model, depend on input assumptions and material data quality. Do not present Phases output as validated engineering data without reviewing it. The chat itself carries the same warning under the composer: "Phases can make mistakes. Check important info."
- It does not label a cooling rate as a water, oil or air quench. A number is a number unless you supplied that mapping and the solver models it.
- It does not report per-phase hardness. Predicted hardness is a bulk, mixture value.
- It does not accept file uploads in chat, and it does not expose an unauthenticated public API for third-party simulation runs. The one supported programmatic surface is an authenticated MCP connection — see Use Phases from an MCP client.
The full list lives in Known limits. The evidence behind the physics is in How we validate, with the detail split into hardness validation and RSW validation.
Where to start#
Run something. Your first simulation takes about five minutes and uses a prompt you can paste as-is. Unfamiliar terms are defined in the Glossary.