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An Indian auto-component supplier outsources surface treatment (zinc / nickel-chrome / e-coat plating) and heat treatment (carburising, nitriding, induction hardening, normalising) to specialised job-workers and must reconcile per-challan dispatched weight versus returned weight under Rule 55 / Section 143 of the CGST Act, with structural weight loss of 0.5 to 3 percent per process that the contract recognises as in-band, ITC-04 quarterly filing tying outbound challans to receipt-backs and one-year clock, conversion-service GST at 18 percent under HSN 9988 on the job-worker invoice, Section 194C TDS on the conversion payment, and the trivalent-chrome regulatory migration affecting plating-rate contracts.
Maintain a job-work challan register per Rule 55 challan with original dispatched weight per part per heat lot per job-worker, expected per-process weight-change band, return-clock per Section 143. On receipt-back challan, tie returned weight to dispatched weight within band; out-of-band triggers reconciliation. Run ITC-04 quarterly extract per job-worker per challan. Process the job-worker invoice at conversion rate per HSN 9988 with 18 percent GST, deduct Section 194C TDS per the new payment-code rail, and post to job-work conversion expense. Maintain trivalent-versus-hexavalent chemistry mapping per plating line for rate-application discipline. Surface clock-expiry alerts at six and ten months from dispatch.
Job-worker master with GSTIN, PAN, contracted rate per process per part, weight-change band per process; per-challan register with outbound and inbound legs under Rule 55; ITC-04 export template with quarterly cadence and one-year clock per dispatch; per-process weight-change band master (carburising, nitriding, induction hardening, normalising, zinc plating, nickel-chrome plating, e-coat); chemistry-type flag (trivalent versus hexavalent) per plating line; Section 194C TDS rate matrix under the new payment-code rail; Form 27EQ and Form 26Q export integration.
A challan-level job-work reconciliation register per Rule 55 challan with one-year clock and out-of-band weight-change alerts; quarterly ITC-04 export ready for GST portal upload reconciled to the books; job-worker invoice match against dispatched challan and conversion-rate master; Section 194C TDS deduction with payment-code 26Q lineage; chemistry-type audit trail for plating lines supporting OEM-driven trivalent migration; and a clock-expiry dashboard surfacing dispatches at six and ten months from challan date.
A fastener Tier-1 in the Faridabad belt makes high-tensile bolts, nuts and threaded fasteners for Tata Motors, Ashok Leyland and Maruti Suzuki Tier-1 sub-assemblers. The shop floor does cold heading, thread rolling and primary machining in-house — but every fastener leaves the plant once or twice for outside processing before it ships. Heat-treatment (typically carburising for case-hardened bolts, induction hardening for shoulder bolts, normalising for medium-carbon nuts) goes to one of three heat-treaters in Faridabad and Ballabgarh. Zinc plating goes to eight platers across NCR — chosen by part-number, by chrome chemistry, by capacity availability. Roughly 12 metric tonnes a month moves out on Rule 55 delivery challans to platers, another 16 metric tonnes a month moves out to heat-treaters. By the end of the quarter, the ITC-04 quarterly filing must declare every challan, tie every receipt-back, surface every pending challan against the Section 143 one-year clock, and reconcile the in-band weight loss across eight plating job-workers and three heat-treatment job-workers. This is heat treatment plating job work reconciliation auto component India — outsourced metallurgy that the principal still owns the tax exposure on.
Quick reference
| Concept | Treatment | Regulator / standard | Tax leg |
|---|---|---|---|
| Outbound dispatch to job-worker | Rule 55 challan from principal | CBIC | No GST on outbound |
| Section 143 clock — inputs | One-year return | Section 143(1) | Beyond one year = deemed supply |
| Section 143 clock — capital goods | Three-year return | Section 143(1) | Dies, fixtures, jigs |
| ITC-04 filing | Quarterly, due 25th of next month | GST portal | Every challan, every job-worker |
| Job-worker invoice | Conversion only, no substrate value | Schedule II CGST Act | 18% GST under HSN 9988 |
| TDS on conversion payment | Section 194C on payment to job-worker | IT Act | New payment-code rail (1001-1092) |
| Plating chemistry | Trivalent migrating from hexavalent | SPCB / REACH-aligned | Rate impacts contract |
| Process weight loss | 0.5-3% per process, structural | OEM-supplier contract | In-band absorbed, out-of-band reconciled |
Section 143 of the CGST Act in one paragraph
Section 143 of the Central Goods and Services Tax Act lets a registered principal send inputs or capital goods to a job-worker on a delivery challan under Rule 55 without paying GST on the outbound movement, provided the material returns as inputs or finished goods within one year for inputs (three years for capital goods such as moulds, dies and fixtures). If the material fails to return within the clock, the original dispatch is deemed a supply on its original date, with GST and 18 percent interest under Section 50 from that original date. The principal must:
- File ITC-04 quarterly, due by the 25th of the month following the quarter, disclosing all challans dispatched, received back and pending against the clock.
- Declare the job-worker’s premises as an additional place of business if material is dispatched directly from there to the principal’s customer.
- Maintain the inbound and outbound challan series, reconciled per challan against the one-year window.
The job-worker raises its own tax invoice for the conversion service only at 18% GST under HSN 9988 — never on the substrate value. The principal absorbs the conversion cost net of input tax credit on the GST paid to the job-worker. The challan-mechanics framework is in Rule 55 delivery challan in auto component job work; the filing mechanics are in ITC-04 filing step-by-step.
The yield-loss issue: why dispatched and returned challan weights cannot match
This is the structural problem that distinguishes job-work reconciliation from a normal three-way match. The returned challan weight is not supposed to equal the dispatched challan weight — it is supposed to differ by a contracted band determined by the process chemistry. The reconciliation has to recognise the in-band loss as routine and surface only the out-of-band variance.
Heat-treatment weight changes
| Process | Typical net weight change on returned challan |
|---|---|
| Normalising | Negligible (−0.05 to 0% from oxidation scale) |
| Stress relieving | Negligible |
| Through-hardening (oil or water quench) | −0.3 to −0.6% (quench scale + descale) |
| Carburising (gas or pack, with quench-temper) | −0.5 to −1.5% (case scale + quench scale) |
| Nitriding (gas or plasma) | Negligible to +0.1% (nitrogen pickup) |
| Induction hardening + temper | −0.3 to −0.8% (localised scale) |
| Salt-bath austempering | −0.3 to −0.7% |
Plating and surface-treatment weight changes
| Process | Typical net weight change on returned challan |
|---|---|
| Zinc electroplating (5-15 micron) | −0.5 to +0.3% (pickling loss vs deposit gain) |
| Nickel-chrome plating (decorative) | +0.1 to +0.4% (small gain) |
| Hard chrome plating (functional, 25-100 micron) | +0.5 to +1.5% (substantial deposit) |
| E-coat (cathodic electrodeposition, 18-25 micron) | +0.3 to +0.8% |
| Phosphating (zinc or manganese) | +0.1 to +0.3% |
| Powder coating | +0.5 to +1.0% (substantial deposit) |
| Anodising (aluminium) | Negligible to +0.2% |
Two things must be in the contract per part per process: (1) the expected net weight-change band so that in-band variance is absorbed, and (2) the out-of-band recovery mechanism — either supplier-recoverable from job-worker on adverse, or job-worker-credit on favourable. Without the contracted band, the ITC-04 reconciliation either tolerates everything (no control) or rejects everything (false alarms on routine loss).
The trivalent-chrome migration
Traditional hexavalent (Cr VI) chrome plating uses chromic acid baths that release hexavalent chromium into wash water and fumes. Hexavalent chromium is a confirmed human carcinogen, and regulatory controls have tightened progressively:
- EU REACH restrictions on hexavalent chromium use in plating, with exemption requirements that auto OEMs have to renew periodically.
- Indian State Pollution Control Board discharge limits on hexavalent chromium in effluent, increasingly tightened.
- OEM end-of-life vehicle directives discouraging hexavalent chromium in supplied components, especially for European-owned OEMs in India.
Trivalent (Cr III) chemistry replaces hexavalent in the plating bath. It is environmentally safer but more expensive per square decimetre of plated area, gives a slightly bluer chrome appearance, and requires tighter bath-chemistry control (pH window, brightener concentration, temperature). The transition affects:
- The plating-rate contract — trivalent typically carries a 10-20% rate premium per square decimetre over hexavalent.
- The job-worker capability map — not every NCR or Pune plater has a trivalent line.
- The OEM audit — increasingly, the OEM will require trivalent on safety-critical or visible-decorative parts and will audit plating-line chemistry generation.
The principal’s reconciliation must hold a chemistry-type flag (trivalent versus hexavalent) per plating job-worker per line, so the right rate is applied to the right invoice and so the OEM-required parts go only to compliant lines.
ITC-04 challan-return tracker template
Drop in your Rule 55 challan series, dispatch dates and job-worker GSTINs to see the quarterly ITC-04 view — what to file, what’s pending against the one-year clock, what’s at risk of deemed supply.
Open the ITC-04 tracker template →The TDS rail on the job-worker payment
When the principal pays the job-worker for the conversion service, Section 194C TDS applies under the new payment-code rail (the 1001-1092 series operative under the Income Tax Act 2025 from 1 April 2026). Rate: 1 percent if the job-worker is an individual or HUF, 2 percent if any other entity, on the conversion charge net of GST, subject to single-payment threshold of ₹30,000 and aggregate annual threshold of ₹1,00,000. The deduction is captured in Form 26Q quarterly, the job-worker receives Form 16A, and the buyer-side credit flows through Form 26AS.
The new payment-code lineage replaces the legacy 194C TDS section-code lineage for fresh payments dated 1 April 2026 onwards. Pre-1 April 2026 deductions follow the legacy lineage through to their full TDS lifecycle. The wider Section 194C job-work mechanics specific to auto components are in Section 194C TDS auto component job work.
Worked example — Faridabad fastener Tier-1, 12 MT/month plating, 16 MT/month heat-treat
The fastener Tier-1 introduced at the top runs the following monthly job-work profile:
- Plating outbound: 12.0 MT across eight zinc-plating job-workers in NCR, on 96 Rule 55 challans (12 parts × 8 platers average).
- Heat-treatment outbound: 16.0 MT across three job-workers in Faridabad and Ballabgarh, on 42 Rule 55 challans.
- Process mix: 60% carburising, 25% induction hardening, 15% normalising on heat-treat; 90% trivalent zinc, 10% hexavalent on plating (the latter for legacy non-OEM-restricted commercial parts).
- Contracted weight-change bands: per the bands in the tables above per process.
Plating reconciliation extract for one challan
A delivery challan dated 03 June 2026, Rule 55 series CH/26-27/PL/0142, dispatches 245 kg of M10 × 75 high-tensile bolts to job-worker JW-PL-04 (Plater) for trivalent zinc plating, 8-micron deposit, OEM Tata Motors program.
- Outbound dispatched weight: 245.0 kg (memorandum-only, no GST, Section 143 clock starts).
- Job-worker conversion rate: ₹14.50/kg trivalent zinc 8-micron, contracted.
- Returned challan dated 06 June 2026, Rule 55 series CH/26-27/JW-PL-04/0083, receipt-back weight: 245.6 kg.
- Net weight change: +0.24% (deposit gain).
- Contracted band: −0.5% to +0.3%. In-band — no exception.
- Job-worker tax invoice: 245.0 × ₹14.50 = ₹3,552.50, plus 18% GST under HSN 9988 = ₹4,191.95. TDS under Section 194C at 2% (corporate job-worker) on ₹3,552.50 = ₹71. Net payable ₹4,120.95.
- ITC-04 entry created with both challan numbers and the conversion-invoice cross-reference.
Heat-treatment reconciliation extract for one challan
A delivery challan dated 14 May 2026, Rule 55 series CH/26-27/HT/0078, dispatches 580 kg of M12 case-hardened wheel-bolt blanks to job-worker JW-HT-02 for carburising and quench-temper, OEM Maruti Suzuki program.
- Outbound dispatched weight: 580.0 kg.
- Job-worker conversion rate: ₹38.00/kg carburise+quench+temper, contracted.
- Returned challan dated 18 May 2026, Rule 55 series CH/26-27/JW-HT-02/0034, receipt-back weight: 575.4 kg.
- Net weight change: −0.79% (scale + descale).
- Contracted band for carburise+quench: −0.5% to −1.5%. In-band — no exception.
- Job-worker tax invoice: 580.0 × ₹38.00 = ₹22,040, plus 18% GST = ₹26,007.20. TDS under Section 194C at 2% on ₹22,040 = ₹441. Net payable ₹25,566.20.
Quarterly ITC-04 summary
For Q1 FY 2026-27, the ITC-04 extract shows:
- Total challans dispatched in quarter: 411 (plating 286, heat-treat 125).
- Total challans received back in quarter (including pre-quarter dispatches): 397.
- Open challans at quarter-end: 14, all dispatched within the quarter, all well inside the one-year clock.
- Out-of-band weight-variance exceptions: 6 — investigation revealed one weighbridge calibration drift (corrected), two part-mix dispatches that the contracted band did not anticipate (contract amendments raised), three legitimate within-process variance just outside the band (absorbed by management approval).
The Q1 ITC-04 is filed on 22 July 2026 (three days before the 25 July due date) with no pending-clock breach. The Section 194C TDS rail across all conversion payments for the quarter, totalling ₹3.2 crore conversion across job-workers, is fully captured in Form 26Q and reconciled to Form 26AS.
How heat-treatment and plating reconciliation tie into the wider auto stack
Heat-treatment and plating job work sits at the intersection of free-issue material accounting, ITC-04 filing, Section 143 deemed supply discipline and Rule 55 delivery challan. The Section 194C TDS rail on conversion payments is set out in Section 194C TDS for auto component job work. It is one rail inside automotive component manufacturing reconciliation. For the ACMA framework on outsourced surface-treatment job work and heat-treatment yield benchmarks see the Automotive Component Manufacturers Association of India (ACMA).
What automated reconciliation changes
Manual heat-treatment and plating job-work reconciliation across dozens of job-workers and hundreds of monthly challans is a clock-tracking discipline that breaks under volume — and where ITC-04 quarter-end scrambles to reconcile half a year of challans typically surface deemed-supply exposure on a handful of forgotten dispatches. Purpose-built auto-component reconciliation software India closes the dispatched-to-returned challan match per Rule 55 challan, drives the Section 143 one-year clock with six- and ten-month alerts, ties job-worker invoices to contracted rates and weight-change bands, reconciles in-band loss as routine and surfaces out-of-band variance for investigation, and prepares the quarterly ITC-04 extract for direct portal upload. TransactIG carries 24+ industry presets including job-work configurations for ITC-04, weight-change-band reconciliation, trivalent-versus-hexavalent chemistry tracking and Section 194C TDS payment-code mapping. Customer outcomes include match-rate improvement from 51% to 88%. Build is two-to-four weeks on AWS Mumbai (ISO 27001:2022). For the inbound match discipline across challan, weighbridge and job-worker invoice see three-way matching software India.