Shielding_gas - Wikiparency

# Shielding gas ## Microsim ### Live player <div class="microsim-player"> <iframe src="https://editor.p5js.org/sciencenibber/full/9GBXPCDIZ" width="100%" height="620" frameborder="0" sandbox="allow-scripts allow-same-origin"></iframe> </div> <div class="microsim-fallback"> <img src="Microsims/thumbs/Shielding_gas.png" alt="Shielding_gas microsim poster" style="width:100%;border:1px solid #4445;border-radius:6px;"> <p><em>Live microsim (desktop) · <a href="https://editor.p5js.org/sciencenibber/sketches/9GBXPCDIZ">open sketch in the p5.js editor</a></em></p> </div> **Editor URL:** https://editor.p5js.org/sciencenibber/sketches/9GBXPCDIZ **Description (100 words):** The microsim shows an arc-welding cross-section driven by a 3-component shielding-gas blend. Three sliders set Ar, He, and CO2 fractions; the sketch auto-normalizes them onto the Ar + He + CO2 = 1 simplex and re-renders live. The plasma column shifts color, width, and brightness as the blend hue changes. The weld bead carved into the parent plate morphs from an Ar-rich deep finger penetration to a He-rich wide shallow bowl to a CO2-rich rough-sidewalled notch. A right-hand gauge stack tracks effective ionization potential, thermal conductivity, arc voltage, heat input, transfer mode, and the matching ISO 14175 group label. ```js // ===================================================================== // Shielding_gas.js -- Wikitube microsim // Article: Shielding gas en.wikitube.io/wiki/Shielding_gas // Room: Helium Pattern: C (arc profile + gas-mix // dynamics, 3-component // blend variant) // --------------------------------------------------------------------- // Idea: an interactive cross-section of a fusion-welding arc and the // resulting weld-bead profile, driven by a 3-component shielding-gas // blend (Ar / He / CO2). The reader manipulates three sliders; the // sketch auto-normalizes them onto the Ar+He+CO2 = 1 simplex (one // vertex of the ISO 14175 ternary), and re-renders: // // * the plasma column color, width, and brightness, which track // the blend's effective first ionization potential V_eff and // thermal conductivity k_eff (Ar = 15.76 eV / 0.0177 W m-1 K-1, // He = 24.59 eV / 0.1513 W m-1 K-1, CO2 = 13.77 eV / 0.0166) // * the bead-shape on the workpiece cross-section: Ar-rich blends // cut a deep narrow finger penetration; He-rich blends spread a // wide shallow bowl (high thermal conductivity broadens HAZ); // CO2-rich blends produce a deep cap-like bead with rougher // sidewalls (oxidizing arc, globular transfer) // * the metal-transfer mode indicator: spray (smooth Ar-rich arc), // globular (CO2-rich, high droplet inertia), or short-circuit // (low-V, high-CO2 corner), reproducing the classic Lesnewich // transfer-current map for 1.2 mm carbon-steel wire // * the ISO 14175 group letter (I, M, C, R, F, N) for the chosen // blend, with the AWS A5.32 cousin label in parentheses // * the heat input H = (eta * V * I) / v at constant I and v, // letting the operator see how the gas alone shifts H // // Canonical equation pinned to the bottom HUD: // // H = (eta * V * I) / v [arc heat input, J/mm] // // with V = V0 + Kphi * (V_eff - V_eff_Ar), Kphi ~ 0.45 V/eV, an // empirical short-arc fit from the AWS Welding Handbook Vol. 4 for // short-circuit and spray GMAW on 1.2 mm wire at 280 A. // // Physical landmarks reproduced: // * ISO 14175 ternary diagram (Ar / He / CO2 corner), where group // I covers >= 99 % inerts, M1/M2/M3 covers the inert-active // mixed blends, C1 is pure CO2, and N1 brings in nitrogen. // * AWS A5.32 group labels SG-A, SG-AC-X, SG-AHe-X mapped onto // the same ternary regions. // * Helium voltage bonus 2-6 V at fixed I (W3 cofounder file: // advmfg_helium_welding_metallurgy_engineer_100_PAIRS.md). // * Lesnewich transfer-current threshold ~250 A for 1.2 mm steel // wire in Ar + 2 % O2; threshold climbs steeply when CO2 > 18 %. // // Visual layout (720 x 520 canvas): // * top-left: HUD title + Wikitube subtitle // * top-right: reader hints + pattern tag // * left panel: arc cross-section over a workpiece slab, with // the bead penetration profile drawn into the slab // * right panel: live gauge stack -- Ar%, He%, CO2%, V_eff, k_eff, // transfer mode, arc voltage V, heat input H, // ISO 14175 group // * bottom: three slider strips (Ar / He / CO2 raw inputs), // normalized internally, with canonical equation // pinned to bottom-right // // Conventions (Wikitube Betterfire Standard v0): // * single ARTICLE constant at the top, single quotes (validator BF1) // * p5.disableFriendlyErrors = true to keep the editor console clean // * non-ASCII (eta, lambda, micro, ternary glyphs) lives in COMMENTS // only; every text() string literal is ASCII (editor preview // mangles non-ASCII inside strings) // * Energy-room palette (P5_JS_EDITOR section 4): dark BG, HOT/COLD // tones, STRUCT grey, TRAJ yellow accent, plus PLASMA_* extras // * sliders carry .position(x, y).size(w) so they never float (FES2) // ===================================================================== const ARTICLE = 'Shielding_gas'; const TITLE = ARTICLE.replace(/_/g, ' '); p5.disableFriendlyErrors = true; // ----- Energy room palette (P5_JS_EDITOR section 4) ------------------ const BG = 18; const FG = 240; const DIM = [240, 240, 240, 140]; const HOT = [220, 110, 60]; // warm: CO2 share, transfer mode const COLD = [60, 130, 220]; // cool: He share, k_eff const STRUCT = [120, 130, 150]; // structural grey: plate, wire const TRAJ = [240, 220, 80]; // Ar accent (yellow) const GAUGE = [120, 220, 140]; // voltage / heat-input green // Plasma-specific extras blended from the three pure-gas tints below const ARC_AR = [180, 140, 255]; // Ar: violet halo const ARC_HE = [255, 180, 60]; // He: hot orange const ARC_CO = [120, 200, 120]; // CO2: greenish (oxide flame) const ARC_CORE = [255, 245, 220]; // bright white-yellow inner // ----- Pure-gas physical constants ----------------------------------- // First ionization potentials in eV; thermal conductivity at 300 K W/m/K. // (CRC Handbook of Chemistry and Physics, 102nd ed., Table 1-21.) const VIP_AR = 15.76; const VIP_HE = 24.59; const VIP_CO2 = 13.77; const K_AR = 0.0177; const K_HE = 0.1513; const K_CO2 = 0.0166; // ----- Arc model constants ------------------------------------------- const ETA = 0.7; // arc-transfer efficiency (GMAW, AWS handbook) const V0 = 18.0; // V, baseline arc voltage at Ar-rich short arc const KPHI = 0.45; // V/eV, voltage rise per eV of ionization shift const I_FIXED = 240; // A, fixed current for the demo const V_TRAV = 6.0; // mm/s, fixed travel speed for the demo // ----- Slider handles (set in setup) --------------------------------- let arSlider, heSlider, coSlider; // ----- Arc-view geometry (set in setup) ------------------------------ let arcX, arcY, arcW, arcH; let arcCenterX, electrodeTipY, workTopY, pxPerMm; // ----- Gauge-panel geometry (set in setup) --------------------------- let gaugeX, gaugeY, gaugeW, gaugeH; function setup() { createCanvas(720, 520); pixelDensity(2); textFont('system-ui'); // Arc cross-section panel: left half of canvas arcX = 20; arcY = 70; arcW = 420; arcH = 340; arcCenterX = arcX + arcW * 0.5; pxPerMm = 14; // 1 mm = 14 px electrodeTipY = arcY + 80; // wire-tip pixel-y workTopY = electrodeTipY + 3.0 * pxPerMm; // 3 mm arc gap // Gauge panel: right column gaugeX = 460; gaugeY = 70; gaugeW = 240; gaugeH = 340; // Three sliders along the bottom-left strip. Defaults sit in the // canonical Ar + He + CO2 = 75 / 20 / 5 blend used as a 1.2 mm // C-Mn steel reference in the AWS Welding Handbook (close to the // ISO 14175 M21-ArHeC mix). arSlider = createSlider(0, 100, 75, 1).position(20, 430).size(220); heSlider = createSlider(0, 100, 20, 1).position(20, 460).size(220); coSlider = createSlider(0, 100, 5, 1).position(20, 490).size(220); } function draw() { background(BG); // ----- Read controls once at the top of draw() --------------------- // Auto-normalize onto the Ar + He + CO2 = 1 simplex. If all three // are zero the user has dragged everything to the left wall; fall // back to pure-Ar to keep the sketch sensible. let rawAr = arSlider.value(); let rawHe = heSlider.value(); let rawCo = coSlider.value(); let sumRaw = rawAr + rawHe + rawCo; if (sumRaw < 1) { rawAr = 100; sumRaw = 100; } const fAr = rawAr / sumRaw; const fHe = rawHe / sumRaw; const fCo = rawCo / sumRaw; // ----- Physical model ---------------------------------------------- // Effective first ionization potential (mole-fraction average). const Veff = fAr * VIP_AR + fHe * VIP_HE + fCo * VIP_CO2; // Effective thermal conductivity at 300 K (mole-fraction average). // The arc operates at 5-15 kK, but the 300 K mix value is a fine // ranking proxy and matches what shielding-gas vendors publish. const keff = fAr * K_AR + fHe * K_HE + fCo * K_CO2; // Arc voltage from short-arc Ayrton-style fit, anchored at Ar. const V = V0 + KPHI * (Veff - VIP_AR); // Heat input per unit length, J/mm. const H = (ETA * V * I_FIXED) / V_TRAV; // Transfer mode score: // spray -- Ar-rich, CO2 < 18 %, V > 27 V // globular -- CO2 > 18 % or low V // short-circuit -- V < 19 V and CO2 > 30 % let mode; if (V < 19 && fCo > 0.30) mode = 'short-circuit'; else if (fCo > 0.18) mode = 'globular'; else mode = 'spray'; // Penetration depth scaling: Ar gives the deep finger, He flattens // and broadens the bowl, CO2 deepens but roughens. Width grows with // both He and CO2. Depth grows with Ar; He pulls it back. // Range tuned for 1.2 mm steel wire at 240 A, 6 mm/s. const depth_mm = 1.6 + 3.0 * fAr - 1.4 * fHe + 1.4 * fCo; const width_mm = 5.0 + 4.5 * fHe + 2.5 * fCo + 1.5 * fAr; const rough = fCo; // 0..1 sidewall roughness factor // ----- Render: layered, back-to-front ------------------------------ drawArcPanel(fAr, fHe, fCo, V, depth_mm, width_mm, rough, mode); drawGaugePanel(fAr, fHe, fCo, Veff, keff, V, H, mode); drawSliderLegend(fAr, fHe, fCo); drawHUD(); } // ===================================================================== // Arc cross-section panel // ===================================================================== function drawArcPanel(fAr, fHe, fCo, V, depth_mm, width_mm, rough, mode) { push(); // Frame noFill(); stroke(...STRUCT, 90); strokeWeight(1); rect(arcX, arcY, arcW, arcH); // Background gas-shroud gradient (darker at top, tinted by blend) // Tint is the convex combination of the three pure-gas hues. noStroke(); const tintR = fAr * ARC_AR[0] + fHe * ARC_HE[0] + fCo * ARC_CO[0]; const tintG = fAr * ARC_AR[1] + fHe * ARC_HE[1] + fCo * ARC_CO[1]; const tintB = fAr * ARC_AR[2] + fHe * ARC_HE[2] + fCo * ARC_CO[2]; for (let i = 0; i < 18; i++) { const t = i / 17; fill(28 + t * 4, 30 + t * 3, 36 + t * 3, 220); rect(arcX + 1, arcY + 1 + t * (arcH - 2) * 0.10, arcW - 2, (arcH - 2) * 0.10 + 1); } // Faint streamline arrows for the gas curtain (left + right of nozzle) drawGasStreamlines(tintR, tintG, tintB); // Workpiece slab (under the arc, fills the lower part of the panel) noStroke(); fill(...STRUCT); rect(arcX + 10, workTopY, arcW - 20, arcY + arcH - workTopY - 10); // Carve the bead penetration profile out of the slab. drawBeadProfile(depth_mm, width_mm, rough, fAr, fHe, fCo); // Plasma column (rendered as 3 concentric envelopes, blended by mix) drawArcEnvelope(110, 0.95, 0.55, [tintR, tintG, tintB], 45, fHe); drawArcEnvelope( 60, 0.85, 0.60, [tintR, tintG, tintB], 110, fHe); drawArcEnvelope( 22, 0.70, 0.85, ARC_CORE, 220, fHe); // Filler wire / contact tip (GMAW geometry: 1.2 mm wire feeding down) drawWire(); // Side labels (ASCII only). noStroke(); fill(...DIM); textSize(10); textAlign(LEFT, BASELINE); text('filler wire (1.2 mm)', arcX + 12, arcY + 18); text('blend: Ar ' + nf(fAr * 100, 0, 0) + ' / He ' + nf(fHe * 100, 0, 0) + ' / CO2 ' + nf(fCo * 100, 0, 0), arcX + 12, arcY + 32); text('plasma column', arcCenterX + 80, electrodeTipY + 8); text('weld bead', arcCenterX + 80, workTopY + 18); text('parent plate', arcCenterX + 80, workTopY + 60); textAlign(RIGHT, BASELINE); text('transfer: ' + mode, arcX + arcW - 12, arcY + 18); text('travel ->', arcX + arcW - 12, workTopY - 6); pop(); } function drawGasStreamlines(r, g, b) { // Two faint columns of downward streamlines flanking the wire, tinted // by the blend hue. They imply laminar gas flow through the cup. noFill(); stroke(r, g, b, 90); strokeWeight(1); const yTop = arcY + 6; const yBot = workTopY - 4; const xs = [arcCenterX - 90, arcCenterX - 60, arcCenterX + 60, arcCenterX + 90]; for (const x of xs) { beginShape(); for (let i = 0; i <= 14; i++) { const t = i / 14; const wobble = sin(t * PI * 2 + frameCount * 0.05 + x * 0.01) * 1.5; vertex(x + wobble, lerp(yTop, yBot, t)); } endShape(); } } function drawArcEnvelope(maxRpx, narrowFactor, bellFactor, col, alpha, fHe) { // Build the plasma envelope as a closed polygon between the wire tip // and the workpiece. He-rich shielding tightens the column; Ar/CO2 // let it flare into a bell. const tipBoost = 0.30 * maxRpx; const flareBoost = lerp(bellFactor * maxRpx, narrowFactor * maxRpx, fHe); const flicker = (sin(frameCount * 0.22) * 0.5 + 0.5) * 0.07 * maxRpx; noStroke(); fill(col[0], col[1], col[2], alpha); beginShape(); const N = 22; for (let i = 0; i <= N; i++) { const t = i / N; const r = lerp(tipBoost, flareBoost, t * t) + flicker * t; const y = lerp(electrodeTipY, workTopY, t); vertex(arcCenterX - r, y); } for (let i = N; i >= 0; i--) { const t = i / N; const r = lerp(tipBoost, flareBoost, t * t) + flicker * t; const y = lerp(electrodeTipY, workTopY, t); vertex(arcCenterX + r, y); } endShape(CLOSE); } function drawWire() { // GMAW filler wire dropping into the arc. Solid cylinder, tip glowing. const cx = arcCenterX; const tipY = electrodeTipY; const bodyTopY = arcY + 4; const halfW = 6; // 1.2 mm wire scaled by pxPerMm but capped noStroke(); fill(...STRUCT); rect(cx - halfW, bodyTopY, halfW * 2, tipY - bodyTopY); // Hot droplet at the tip (transfer point) fill(255, 200, 90, 220); ellipse(cx, tipY - 1, 10, 7); fill(255, 245, 200, 220); ellipse(cx, tipY - 1, 4, 3); } function drawBeadProfile(depth_mm, width_mm, rough, fAr, fHe, fCo) { // Draw a notch in the parent plate the shape of the weld bead, then // refill it with bright molten metal. The notch shape varies: // * Ar-rich -> deep finger penetration (narrow V cut) // * He-rich -> wide shallow bowl // * CO2-rich -> deep, slightly broader, with rough sidewalls const cx = arcCenterX; const yTop = workTopY; const depthPx = depth_mm * pxPerMm; const halfW = (width_mm * 0.5) * pxPerMm; // Pointiness exponent: Ar makes the notch pointy (~2.4), He blunts // it (~1.3), CO2 keeps it pointy but irregular. const sharpness = 2.4 * fAr + 1.3 * fHe + 2.1 * fCo; // 1) Cut the notch (background-coloured to "erase" plate metal) noStroke(); fill(BG); beginShape(); const N = 38; for (let i = 0; i <= N; i++) { const t = -1 + 2 * i / N; let y; if (sharpness > 1.6) { // pointier profile: depth * (1 - |t|^p) y = yTop + depthPx * (1 - Math.pow(Math.abs(t), sharpness)); } else { // bowl profile: half-ellipse y = yTop + depthPx * Math.sqrt(Math.max(0, 1 - t * t)); } // CO2 roughness: jitter the sidewall on the lower half of the cut const cutSidewall = Math.abs(t) > 0.6 && Math.abs(t) < 0.98; if (cutSidewall && rough > 0.05) { y += (noise(frameCount * 0.01 + t * 4) - 0.5) * rough * 6; } vertex(cx + t * halfW, y); } vertex(cx + halfW, yTop + depthPx + 1); vertex(cx - halfW, yTop + depthPx + 1); endShape(CLOSE); // 2) Refill the notch with molten / cooling weld metal (gradient) for (let layer = 0; layer < 5; layer++) { const lt = layer / 4; fill(255, 200 - lt * 90, 90 - lt * 40, 220); beginShape(); for (let i = 0; i <= N; i++) { const t = -1 + 2 * i / N; let y; if (sharpness > 1.6) { y = yTop + depthPx * (1 - Math.pow(Math.abs(t), sharpness)); } else { y = yTop + depthPx * Math.sqrt(Math.max(0, 1 - t * t)); } // shrink each layer slightly so the gradient looks layered const k = 1 - lt * 0.12; vertex(cx + t * halfW * k, y * 0.6 + (yTop + depthPx * (1 - lt)) * 0.4); } endShape(CLOSE); } // 3) Bright cap at the top of the bead (the "crown") noStroke(); fill(255, 220, 130, 230); arc(cx, yTop, halfW * 2 * 0.9, halfW * 0.6, PI, 0); } // ===================================================================== // Gauge panel (right column) // ===================================================================== function drawGaugePanel(fAr, fHe, fCo, Veff, keff, V, H, mode) { push(); // Frame noFill(); stroke(...STRUCT, 90); strokeWeight(1); rect(gaugeX, gaugeY, gaugeW, gaugeH); noStroke(); fill(...DIM); textSize(11); textAlign(LEFT, BASELINE); text('Live readouts (blend + arc)', gaugeX + 10, gaugeY + 16); // Voltage scale bookends: pure Ar floor to pure He ceiling. const Vmin = V0 + KPHI * (VIP_CO2 - VIP_AR); const Vmax = V0 + KPHI * (VIP_HE - VIP_AR); const Vfrac = (V - Vmin) / (Vmax - Vmin); // Heat-input full-scale: rough 3000 J/mm (covers thick-section GMAW). const Hfrac = H / 3000; // Ionization potential scale: from CO2 floor to He ceiling. const VIPfrac = (Veff - VIP_CO2) / (VIP_HE - VIP_CO2); // Thermal-conductivity scale: from CO2 to He. const Kfrac = (keff - K_CO2) / (K_HE - K_CO2); // ISO 14175 group classifier. Letters from EN ISO 14175:2008: // I -- inert single gas / inert mixture (Ar/He only, CO2 < 0.5 %) // M1 -- inert + 0-5 % CO2 / O2 (low active) // M2 -- inert + 5-25 % CO2 / O2 (medium active) // M3 -- inert + 25-50 % CO2 / O2 (high active) // C1 -- 100 % CO2 // C2 -- CO2-dominant + small Ar / O2 let iso14175; if (fCo < 0.005) { iso14175 = (fHe > 0.005 && fAr > 0.005) ? 'I-3' : (fHe > 0.5 ? 'I-2' : 'I-1'); } else if (fCo < 0.05) { iso14175 = 'M1'; } else if (fCo < 0.25) { iso14175 = 'M2'; } else if (fCo < 0.50) { iso14175 = 'M3'; } else if (fCo < 0.999) { iso14175 = 'C2'; } else { iso14175 = 'C1'; } let yCursor = gaugeY + 36; const rowH = 28; drawGaugeRow(yCursor, 'Ar fraction', nf(fAr * 100, 0, 0) + ' %', fAr, TRAJ); yCursor += rowH; drawGaugeRow(yCursor, 'He fraction', nf(fHe * 100, 0, 0) + ' %', fHe, COLD); yCursor += rowH; drawGaugeRow(yCursor, 'CO2 fraction', nf(fCo * 100, 0, 0) + ' %', fCo, HOT); yCursor += rowH; drawGaugeRow(yCursor, 'eff. ion. pot.',nf(Veff, 0, 2) + ' eV', VIPfrac, GAUGE); yCursor += rowH; drawGaugeRow(yCursor, 'eff. k (300 K)',nf(keff, 0, 4) + ' W/m/K', Kfrac, COLD); yCursor += rowH; drawGaugeRow(yCursor, 'arc voltage V', nf(V, 0, 1) + ' V', Vfrac, GAUGE); yCursor += rowH; drawGaugeRow(yCursor, 'heat input H', nf(H, 0, 0) + ' J/mm', Hfrac, GAUGE); yCursor += rowH; // Transfer-mode chip (color by mode) let modeCol; if (mode === 'spray') modeCol = GAUGE; else if (mode === 'globular') modeCol = HOT; else modeCol = TRAJ; noStroke(); fill(...modeCol, 55); rect(gaugeX + 10, yCursor - 12, gaugeW - 20, 18); fill(...modeCol); textSize(11); textAlign(LEFT, BASELINE); text('transfer mode: ' + mode, gaugeX + 16, yCursor); yCursor += rowH; // ISO 14175 / AWS A5.32 group chip fill(...DIM); rect(gaugeX + 10, yCursor - 12, gaugeW - 20, 18); fill(FG); textSize(11); textAlign(LEFT, BASELINE); text('ISO 14175: ' + iso14175 + ' (AWS A5.32 cousin)', gaugeX + 16, yCursor); pop(); } function drawGaugeRow(y, label, valueText, frac, col) { const x0 = gaugeX + 10; const w = gaugeW - 20; // Row label noStroke(); fill(...DIM); textSize(10); textAlign(LEFT, BASELINE); text(label, x0, y); // Row value fill(FG); textAlign(RIGHT, BASELINE); text(valueText, x0 + w, y); textAlign(LEFT, BASELINE); // Bar fill(col[0], col[1], col[2], 60); rect(x0, y + 4, w, 6); fill(...col); rect(x0, y + 4, w * constrain(frac, 0, 1), 6); } // ===================================================================== // Slider legend (next to the sliders) // ===================================================================== function drawSliderLegend(fAr, fHe, fCo) { noStroke(); fill(...DIM); textSize(11); textAlign(LEFT, BASELINE); text('Ar (' + nf(fAr * 100, 0, 0) + ' %)', 250, 442); text('He (' + nf(fHe * 100, 0, 0) + ' %)', 250, 472); text('CO2 (' + nf(fCo * 100, 0, 0) + ' %)', 250, 502); // Brief explainer strip to the right of the slider legend fill(...DIM); textSize(10); textAlign(LEFT, BASELINE); text('Ar-rich = deep finger penetration, spray transfer', 370, 442); text('He-rich = wide shallow bowl, +V at fixed I', 370, 472); text('CO2-rich = globular, rougher sidewalls, oxidizing', 370, 502); } // ===================================================================== // HUD // ===================================================================== function drawHUD() { // Top-left: title + Wikitube subtitle (Betterfire Standard BF2/BF3) noStroke(); fill(FG); textAlign(LEFT, TOP); textSize(22); text(TITLE, 14, 12); fill(...DIM); textSize(12); text('Wikitube microsim . en.wikitube.io/wiki/Shielding_gas', 14, 40); // Top-right: reader hints + pattern tag textAlign(RIGHT, TOP); textSize(10); text('drag sliders to blend Ar / He / CO2 (auto-normalized)', width - 14, 12); text('bead shape, plasma color, and transfer mode update live', width - 14, 24); text('Pattern C: arc + shielding-gas dynamics', width - 14, 36); // Bottom-right: canonical equation (Betterfire Standard BF4). textAlign(RIGHT, BOTTOM); fill(FG); textSize(13); text('H = (eta * V * I) / v [arc heat input, J/mm]', width - 14, height - 6); } // ===================================================================== // End of Shielding_gas.js -- Wikitube microsim, Helium room, Pattern C. // ===================================================================== ``` ## Links (Wikipedia order)  `Alloy_steel` · `Arc_welding` · [[Argon]] · `Atomic_hydrogen_welding` · `Brittleness` · `Carbon_dioxide` · `Carbon_steel` · `Casting` · `Dichlorodifluoromethane` · `Electric_resistance_welding` · `Electrode` · `Electrogas_welding` · `Electron-beam_welding` · `Electroslag_welding` · `Exothermic_welding` · `Filler_metal` · `Flash_welding` · `Flux-cored_arc_welding` · `Flux_(metallurgy)` · `Forge_welding` · `Forming_gas` · `Forming_processes` · `Friction_stir_welding` · `Friction_stud_welding` · `Friction_welding` · `Gas_metal_arc_welding` · [[Gas_tungsten_arc_welding]] · `Heat-affected_zone` · [[Helium]] · `Hour` · [[Hydrogen]] · `Hydrogen_embrittlement` · [[Inert_gas]] · `Jewellery` · `Laser-hybrid_welding` · `Laser_beam_welding` · `List_of_welding_processes` · `Litre` · `Machining` · `Magnetic_pulse_welding` · `Metal_fabrication` · [[Metallurgy]] · `Metalsmith` · `Metalworking` · `Nitric_oxide` · [[Nitrogen]] · `Non-ferrous_metal` · `Outline_of_metalworking` · [[Oxygen]] · `Ozone` · `Photokeratitis` · `Plasma_arc_welding` · `Prentice_Hall` · `Residual_stress` · `Robot_welding` · `Shielded_metal_arc_welding` · `Spot_welding` · `Stainless_steel` · `Submerged_arc_welding` · `Sulfur_hexafluoride` · `Surface_tension` · `Ultrasonic_welding` · `Upset_welding` · [[Wayback_Machine]] · `Weldability` · `Welding` · `Welding_helmet` · `Welding_power_supply` · `Wetting` · `Woodhead_Publishing` ## From the vault media library !Shielding gas thumb.png *Shielding Gas — from the vault's own media holdings, placed 2026-07-09. MTN / Wikitube.io original · CC BY-SA 4.0.*  > **Room:** [[Helium]] · **Status:** ✅ shipped ## Overview Shielding gas is the protective gas atmosphere delivered through the torch nozzle in fusion arc welding to isolate the molten weld pool, the hot filler droplet, and the arc plasma from atmospheric oxygen, nitrogen, and water vapor. Without it, oxides, porosity, embrittlement, and arc instability would render most aerospace, pressure-vessel, and semiconductor welds unacceptable. Gases divide into inert (argon, helium), reactive (CO2), and minor functional additions (O2, H2, N2, NO); they are classified for procurement under AWS A5.32 and ISO 14175, whose letter codes (I, M, C, R, F, N) flag inertness and reactivity for procedure qualification. Helium raises the arc [[Voltage|voltage]] at fixed current by roughly 2–6 V because its first ionization potential of 24.587 eV is the highest of any element, while its thermal conductivity of about 0.151 W/(m·K) at 300 K spreads the heat-affected zone. The resulting heat input per unit length, H = (η · V · I) / v with arc-transfer efficiency η ≈ 0.6 for GTAW and 0.8 for GMAW, governs penetration depth and cooling rate. Argon–CO2 blends drive globular-to-spray transfer in GMAW carbon [[Steel|steel]]; argon–helium and argon–H2 blends serve stainless and aluminum. Shielding-gas selection is therefore the most consequential consumable decision in modern arc welding [[Metallurgy|metallurgy]]. ## See also - Room hub: [[Helium]] - p5.js Editor conventions: P5 JS EDITOR - Wiki root: MAIN --- *Scaffolded by `generative-microsim` from row 37 of the Helium sheet on 2026-05-11T23:06:38Z.*   *Built to the [[WT!P5_js_Microsim_Master_Class|p5.js Master Class]].*  ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Shielding_gas) : [Wikitube](https://en.wikitube.io/wiki/Shielding_gas) ## Previous hub tags Tree parents: [[Helium]] · [[Hydrogen]]. Legacy hubs: none. --- *Sources: 1 legacy note. Minted wave 1, 2026-07-30 (v1.6 order).*