Sweep a weld schedule
Vary current, weld time or electrode force across resistance spot welding runs and compare the nugget outcomes, one confirmed run at a time.
You have a joint to qualify and you want to see where the weldable range sits — how low the current can go before the nugget shrinks below spec, what an extra cycle of weld time buys you, whether dropping electrode force helps or hurts.
Start with the honest answer: there is no sweep parameter in Phases. The spot welding tool takes a single current, a single weld time and a single force. A sweep is repeated runs — one confirmation card and one stored run version per point. That is more deliberate than a batch job, and it is also why every point in your sweep is separately auditable.
The confirmation card is mandatory#
Every spot welding request shows a Configure Simulation card before anything runs. That applies even when you state every parameter yourself — your values are pre-filled into the card, and nothing executes until you press Run Simulation. There is no way to skip it from chat. Plan on one card press per sweep point.
Step 0: start from a calibrated template#
Do not invent a baseline. Ask what has already been calibrated:
Show me the calibrated RSW templates for DP600.
There are 22 templates: 17 symmetric single-grade cases and 5 dissimilar joint pairs. Each carries a calibrated current, pressure and timing, and every one of them names the target nugget-diameter range it was calibrated against — for example the symmetric DP600 1.2 mm case targets 5.5–6.0 mm. Three supported grades — 20MnB8, 25MnB5 and 29MnB7 — have no calibrated template.
Show me only the dissimilar RSW templates.
Step 1: run the baseline#
Spot-weld two 1.2 mm DP600 sheets at 6 kA with 32.7 MPa electrode pressure, 0.42 s weld time and 3 s total time.
Press Run Simulation on the card. Note the peak temperature the summary reports.
Step 2: change one variable at a time#
Repeat that spot weld at 6.5 kA instead.
Now the same weld at 7 kA.
Each of these gets its own card, pre-filled with the values you named. Check the other fields on the card before you press Run — restate anything that matters rather than assuming it carried over. What you can vary, and the range the chat card accepts:
| Parameter | Accepted range on the card | Notes |
|---|---|---|
| Welding current | 1–12 kA (entered as 1000–12000 A) | Only editable in current mode |
| Electrode pressure | 1–50 MPa | |
| Electrode force | 0.5–15 kN | Alternative to pressure; converted using a fixed electrode face area |
| Plate thickness | 0.5–2.5 mm per plate | Top and bottom set independently |
| Coating | On or off per plate | |
| Weld time | 0–1 s | Total time must be greater than or equal to weld time |
| Total time | Any positive value | Includes hold and cooling |
| Microstructure | Off by default | Turn on for phase tracking and hardness |
In voltage mode the voltage field is fixed at 1062.2 and cannot be edited, so a current sweep is the only electrical sweep available from the card.
What you cannot vary: electrode tip geometry, squeeze time, hold time and multi-pulse schedules are not exposed as parameters. The solver runs a fixed 2D axisymmetric electrode and mesh geometry; only plate grade, thickness and coating change the geometry.
Step 3: read the nugget outcome#
The result gallery includes a plot labeled Nugget & HAZ Analysis. It classifies every steel element by the peak temperature it reached during the cycle:
| Zone | Peak temperature threshold |
|---|---|
| Nugget | 1803 K and above |
| Upper HAZ | 1050 K and above |
| Lower HAZ | 750 K and above |
| Base Metal | Below 750 K |
It reports per-plate zone diameters for those four zones. That diameter is the number your sweep is really about — compare it against the AWS D8.1M criterion of 5·√t mm minimum, where t is the thickness of the thinner sheet.
The gallery also gives you Nugget Evolution (animated), Temperature Contours, Temperature History, Nugget Zoom (end of welding) and Nugget Zoom (cooling), among others.
Hardness values only appear on the nugget/HAZ plot when the model has cooled below 473 K (200 °C) by the end of the simulated time and phase data are present — which means microstructure tracking must be on and your total time must be long enough. A run that ends hot reports no hardness.
Two cautions that change how you plan a sweep#
Nugget diameter is quantized by the mesh. It moves in discrete steps rather than continuously. A 0.2 kA increment may produce an identical reported diameter. Space your sweep points widely enough that the change is larger than one mesh step, and do not read fine trends into the diameter series.
The mechanical coupling is experimental and linear thermoelastic only. If you enable it, the card itself warns that plastic flow stress is not active in the current solve. Do not interpret displacement or von Mises output as validated electrode indentation, sheet thinning or expulsion. The flow_stress_model setting is a compatibility field and changing it does not change the result.
Step 4: compare the runs#
List my RSW runs.
Inspect run 4 and show me its plots.
In the simulation panel's Results tab each stored run shows Grades, BC, t_end and Peak T on one row, which makes a current sweep readable at a glance. See Reuse and share runs.
Grade coverage#
Spot welding is limited to 20 grades with 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. Anything else is rejected before the solver starts.
Those 20 grades map onto only two bulk property families — a DC04 family covering all DC and HC grades, and a 22MnB5 family covering all DP grades, all the boron press-hardening grades and EN13261. Two grades inside one family share the same electrical, thermal, density and latent-heat curves, so a thermal-only sweep that changes nothing but the grade within one family has nothing left to vary. A custom chemistry does not create a new spot welding grade; it rides along on one of the 20 base grades, and it only reaches the physics when microstructure tracking is enabled.
Variations#
Force instead of pressure. Switch the card's Mechanical field to Force [kN] and sweep 2, 3 and 4 kN. The card converts to pressure using a fixed electrode face area and still clamps the result to 1–50 MPa.
Weld time. Repeat that weld with 0.30 s weld time and …with 0.55 s weld time, keeping total time at 3 s.
Dissimilar joint. Spot-weld 1.0 mm DC04 to 1.5 mm 22MnB5 and show me the nugget and HAZ analysis. Set the two plate grades independently on the card.
Budget the runs. The in-process solver is stopped after 900 seconds. Microstructure-enabled runs take substantially longer than thermal-only runs, so leave it off while you are locating the range and turn it on for the two or three points you want phase and hardness detail on.