If you’ve ever raised a GST invoice for fabrication work and stared at the HSN/SAC field wondering what number goes there, you’re not alone. Contractors, fabricators, and procurement teams get this wrong constantly, and a wrong code on your invoice can mean a mismatch notice from the GST department, a blocked ITC claim, or worse, a demand with penalty.
Here’s the core problem: fabrication sits on an awkward line. Sometimes it’s a supply of goods (you’re delivering a fabricated MS structure). Sometimes it’s a supply of services (you’re working on the client’s material at their site). GST treats these two scenarios completely differently, with different HSN codes, different SAC codes, and different tax rates.
In this guide, you’ll find the exact HSN and SAC codes for MS fabrication work, steel fabrication, aluminium fabrication, and job work on metal structures. You’ll also understand when to use a goods code vs a service code, what 998873 means, and how to pick the right GST rate for your invoice — without calling a CA every time.
I’ve spent years working with fabrication contractors, structural steel suppliers, and industrial clients navigating GST compliance. The confusion in this space is real, and most of what’s written online is either too generic or just plain outdated.
What Is an HSN Code?
HSN stands for Harmonised System of Nomenclature. It’s a 6-to-8-digit international product classification system that India adopted under GST. Every physical good sold in India needs one. The CBIC (Central Board of Indirect Taxes and Customs) maps GST rates to these codes.
An HSN code is a standardised 6–8 digit number that classifies physical goods for GST purposes. It works by grouping products into chapters (2 digits), headings (4 digits), and sub-headings (6–8 digits) based on material composition and product type. Most commonly used on B2B invoices where the buyer claims input tax credit.
SAC stands for Services Accounting Code — the equivalent classification for services under GST. Where HSN covers goods, SAC covers what you do.
Fabrication work is complicated because the same job can be either. A structural MS fabricator who purchases raw MS angle, fabricates trusses in his workshop, and delivers the finished structure to the client is supplying goods. A job worker who goes to the client’s site, uses the client’s MS material, and does cutting, welding, and assembly is supplying a service.
The GST rule is clear: if you supply a fabricated product, use an HSN code. If you supply fabrication as a service (including job work), use a SAC code.
HSN Codes for MS and Steel Fabrication Products (Goods)
When you manufacture and supply fabricated goods made of mild steel or structural steel, Chapter 73 of the HSN schedule applies. Chapter 73 covers “Articles of Iron or Steel.”
The primary HSN codes for MS and steel fabrication products fall under Chapter 73 (Iron and Steel Articles). The most relevant heading is 7308, which covers structures and parts of structures made of iron or steel — including bridges, towers, columns, beams, frames, doors, and similar fabricated items. GST rate on most Chapter 73 fabricated structural items is 18%.
Here are the most-used Chapter 73 HSN codes for fabricated MS and steel goods:
| HSN Code | Description | GST Rate |
|---|---|---|
| 7308 | Structures and parts of structures of iron or steel (towers, trusses, columns, frames, bridges, shuttering) | 18% |
| 7308 10 | Bridges and bridge sections | 18% |
| 7308 20 | Towers and lattice masts | 18% |
| 7308 30 | Doors, windows, and frames | 18% |
| 7308 40 | Equipment for scaffolding, shuttering, and prop systems | 18% |
| 7308 90 | Other structures (sheds, columns, beams, platforms) | 18% |
| 7326 | Other articles of iron or steel | 18% |
| 7214 | Bars and rods of iron or non-alloy steel | 18% |
For MS fabrication work where you supply a finished product — a fabricated shed, staircase, railing, structural column, or mezzanine floor — HSN 7308 90 is the most commonly applicable code.
For MS pipes and pipe fittings fabricated and supplied, look at HSN 7304 (seamless tubes/pipes) or 7306 (welded tubes/pipes).
What “MS Structure” Means for GST Classification
MS (Mild Steel) structures include everything from factory sheds and storage platforms to industrial frames and staircase structures. All of these, when fabricated and supplied as finished goods, fall under HSN 7308.
The GST rate of 18% applies across the board. There is no concessional rate for MS structural work when supplied as goods.
SAC Code for Fabrication Work as a Service (998873 Explained)
Here’s where most people get confused. If you’re not supplying fabricated goods but instead doing fabrication on someone else’s material, you’re providing a service. GST classifies this as “Manufacturing Services on Physical Inputs Owned by Others” — what used to be called job work.
SAC code 998873 covers “treatment and coating of metals and machining services,” which under the broader GST framework for manufacturing services covers metal fabrication work done as a service on materials supplied by the client. The applicable GST rate is 18%. This code applies when a fabricator works on material owned by the principal manufacturer or client.
The full SAC hierarchy looks like this:
| SAC Code | Description | GST Rate |
|---|---|---|
| 9988 | Manufacturing services on physical inputs owned by others | 18% |
| 998871 | Structural metal product manufacturing services | 18% |
| 998872 | Fabricated metal product manufacturing services | 18% |
| 998873 | Treatment and coating of metals and machining services | 18% |
| 998874 | Cutlery, hand tool, and general hardware manufacturing services | 18% |
SAC 998871 is the most directly applicable code for structural MS fabrication services — making it the correct choice for most contractors doing job work on iron/steel structures.
SAC 998873 specifically applies when the work involves surface treatment, galvanizing, powder coating, or machining as part of the fabrication process.
When to Use 998871 vs 998873
Use 998871 when your scope of work is: cutting, drilling, welding, assembling, and erecting steel structures from material supplied by the client.
Use 998873 when your work is primarily: blasting, priming, painting, galvanizing, powder coating, heat treatment, or precision machining of metal components.
Many fabrication contracts involve both. In that case, the principal supply determines the code. If the primary work is structural assembly and the surface treatment is incidental, use 998871.
HSN Code for Aluminium Fabrication Work
Aluminium fabrication follows a different chapter entirely. Chapter 76 of the HSN schedule covers “Aluminium and Articles Thereof.”
The HSN code for aluminium fabrication work (supply of goods) is 7610, which covers aluminium structures and parts of structures including doors, windows, and frames. For aluminium fabrication as a service, SAC 998872 applies. The GST rate on aluminium fabricated structures is 18%.
Key HSN codes for aluminium fabrication:
| HSN Code | Description | GST Rate |
|---|---|---|
| 7604 | Aluminium bars, rods, and profiles | 18% |
| 7608 | Aluminium tubes and pipes | 18% |
| 7610 | Aluminium structures and parts (windows, doors, frames, railings) | 18% |
| 7616 | Other articles of aluminium | 18% |
HSN 7610 10 specifically covers aluminium doors, windows, door frames, window frames, and thresholds — the bread and butter of most aluminium fabrication contractors.
HSN 7610 90 covers other aluminium structures not covered above, including custom architectural metalwork, aluminium cladding systems, and industrial aluminium frames.
MS Fabrication Work HSN Code: Goods vs Service — A Practical Decision Framework
The single most common GST error in fabrication invoicing is using an HSN code when a SAC code should be used, or vice versa. The financial impact is zero (both attract 18% GST in most cases), but the compliance impact can be significant if your category is challenged during audit.
Use this framework to decide:
Step 1 — Who owns the raw material?
- You buy and supply the MS material + do the fabrication → Supply of Goods → HSN 7308
- Client supplies the MS material → Supply of Service → SAC 998871
Step 2 — Is there a works contract? Works contracts (common in construction and civil projects) have their own GST treatment under Section 2(119) of the CGST Act. Works contracts covering immovable property attract 18% GST with a specific SAC of 9954.
Step 3 — Is this for an immovable structure? Fabrication and erection of MS structures permanently attached to land or buildings (like factory sheds, mezzanine platforms bolted to a building) may be classified as a works contract under SAC 995432 or 995433 rather than pure fabrication services.
| Scenario | Code to Use |
|---|---|
| You supply fabricated MS structure (own material) | HSN 7308 90 |
| Job work on client’s MS material (job work) | SAC 998871 |
| Aluminium doors/windows supply | HSN 7610 10 |
| Job work on client’s aluminium | SAC 998872 |
| MS shed erected on client’s property (works contract) | SAC 995432 |
| Metal coating/surface treatment service | SAC 998873 |
GST Rate on Fabrication Work: What Actually Applies in 2025
The short answer: 18% in almost every case. But the nuances matter for ITC.
The GST rate on fabrication work in India is 18% across all major categories — whether classified as goods under Chapter 73 or 76, or as services under SAC 9988 or 9954. Job work on goods other than agricultural produce and textile attracts 18% GST. Works contracts for commercial construction also attract 18%.
A few exceptions exist:
- Job work specifically for the textile sector attracts 5% GST (not relevant for metal fabrication).
- Job work for the food processing sector attracts 5% (not relevant here).
- Government infrastructure contracts have specific reduced rates in some categories.
For ITC purposes: if you’re a registered fabrication contractor receiving MS material from a principal manufacturer for job work, the principal can send goods to you under a delivery challan without payment of GST. You return the fabricated goods within 1 year (3 years for capital goods). GST applies only when the goods are sold/cleared, not during the job work process itself.
Common Mistakes Fabricators Make on GST Invoices
These mistakes come up repeatedly in GST audits for fabrication businesses:
1. Using Chapter 73 HSN codes for job work services The fabricated product code (7308) is for goods. If you’re doing job work, the invoice should show a SAC code, not an HSN code. Mixing these up doesn’t affect the tax amount but raises flags during GSTR reconciliation.
2. Not distinguishing material supply from fabrication service Many fabricators supply both material and labour under one invoice. If the material value exceeds 50% of the total contract value, the entire contract may be treated as a supply of goods. Get clarity on this before invoicing.
3. Using generic SAC 9988 instead of the specific sub-code CBIC expects the most specific SAC code available. Using the broad parent code when a specific 6-digit code exists can lead to classification disputes.
4. Works contract classified as pure fabrication service If your fabrication work is attached to an immovable property (building, land), it’s a works contract under SAC 9954, not a manufacturing service under 9988. This matters significantly for the supplier — certain ITC restrictions apply under works contracts that don’t apply to pure fabrication services.
5. Forgetting to mention HSN/SAC code in invoices Businesses with annual turnover above ₹5 crore must mention 8-digit HSN codes on all B2B invoices. Below ₹5 crore turnover, 4-digit codes are acceptable for B2B invoices.
HSN/SAC Code Quick Reference Table for Fabrication Work
| Type of Work | Supply Type | Code | GST Rate |
|---|---|---|---|
| MS structural fabrication & supply | Goods | 7308 90 | 18% |
| MS fabrication job work | Service | 998871 | 18% |
| Steel structure erection (works contract) | Service | 995432 | 18% |
| Aluminium doors/windows supply | Goods | 7610 10 | 18% |
| Aluminium fabrication job work | Service | 998872 | 18% |
| Metal coating/treatment service | Service | 998873 | 18% |
| MS pipes fabrication & supply | Goods | 7306 | 18% |
| Stainless steel fabricated goods | Goods | 7326 | 18% |
| Industrial machinery fabrication | Goods | Chapter 84 | 18% |
| General metal articles supply | Goods | 7326 | 18% |
What the GST Council and CBIC Say: The Official Position
The CBIC has issued several clarifications on job work and fabrication classification over the years. Circular No. 126/45/2019-GST specifically addressed the distinction between supply of goods and supply of services in the context of job work.
The circular confirms: the critical factor is ownership of the raw material at the time of fabrication. This is the primary test. Secondary tests include the nature of the contract, the site of work, and whether the output is a movable or immovable property.
For fabrication businesses working with large infrastructure clients or PSUs, advance rulings from the Authority for Advance Rulings (AAR) in relevant states provide additional clarity. Maharashtra and Gujarat AARs have both addressed structural steel fabrication classification disputes in the past five years. The consistent finding: supply of fabricated structural steel as goods falls under Chapter 73; fabrication services on customer-owned material fall under SAC 9988.
As a GST practitioner who has reviewed dozens of fabrication contracts across Gujarat and Maharashtra, the most expensive mistake I see is not the wrong HSN code itself — it’s the inconsistency. One invoice uses 7308, the next uses 998871 for identical work. Auditors flag inconsistency faster than they flag an incorrect but consistently applied code. Pick your classification, document your reasoning, and stick to it.
Conclusion
Fabrication work HSN code classification comes down to one fundamental question: are you selling a product or selling a service?
MS and steel fabricated structures supplied as finished goods belong under HSN 7308 90. Aluminium fabricated structures fall under HSN 7610. Fabrication done as job work on client-owned material is a service under SAC 998871 or 998873. Works contracts involving immovable property use SAC 9954.
The GST rate is 18% in all major fabrication categories, so getting the code wrong won’t change your tax liability — but it will create reconciliation mismatches, ITC issues for your clients, and potential audit exposure. For turnover above ₹5 crore, use 8-digit codes on every B2B invoice.
When in doubt, document your reasoning. The classification decision you make should be defensible, consistent, and supported by the nature of your contract. If your business handles both goods supply and job work, maintain separate invoice series for each category to keep your GSTR filings clean.
Frequently Asked Questions
What is the HSN code for fabrication work in India?
For supply of fabricated MS or steel goods, HSN 7308 90 applies. For fabrication as a job work service, SAC 998871 applies. The correct code depends on whether you own the raw material or the client does.
What is 998873 HSN code?
998873 is a SAC (Services Accounting Code) under the GST framework. It covers treatment and coating of metals and machining services — including blasting, painting, galvanizing, and precision machining as fabrication services. The GST rate is 18%.
What HSN code applies to MS structure supply?
MS structures (factory sheds, trusses, columns, frames) supplied as finished goods use HSN 7308 90 under Chapter 73 (Articles of Iron and Steel). GST rate is 18%.
What is the SAC code for aluminium fabrication work?
Aluminium fabrication as a job work service uses SAC 998872. Supply of fabricated aluminium structures as goods uses HSN 7610 (for doors, windows, frames) or HSN 7616 for other aluminium articles.
Is GST on fabrication work 12% or 18%?
The GST rate on fabrication work is 18% for all metal fabrication categories — MS, steel, aluminium, and stainless steel — whether classified as goods or services. There is no 12% rate applicable to standard metal fabrication work.
What is the difference between HSN and SAC codes?
HSN codes classify physical goods (products you manufacture and supply). SAC codes classify services (work you perform). Fabrication of goods you supply = HSN. Fabrication services on client’s material = SAC.
He founded Finance and Tax Guide to simplify complex tax and accounting topics for Indian small businesses, entrepreneurs, and individual taxpayers.
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• GST Registration and Return Filing
• Income Tax Return (ITR) Filing
• TDS and TCS Compliance
• Business Bookkeeping
• Financial Accounting
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