Carbon steel flange price guide: types, grades & cost factors explained

What is harga flange carbon steel?

Harga flange carbon steel adalah harga satuan komponen sambungan pipa berbahan baja karbon yang digunakan untuk menghubungkan pipa, katup, dan peralatan dalam sistem perpipaan industri, dinyatakan per piece atau per kilogram di pasar Indonesia. In practical terms, it is the per-unit cost a procurement team pays to connect two sections of pipe — or to terminate a line — using a disc-shaped steel fitting bolted to a mating surface.

The price range in Indonesia is enormous. A 2-inch carbon steel slip-on flange in Class 150 can cost as little as Rp 85,000, while a 12-inch Weld Neck in Class 600 with a certified Mill Test Report (MTR) can exceed Rp 4,800,000 per piece. That spread — roughly 56× — is not random. It reflects differences in material grade, pressure rating, dimensional standard, manufacturing process, and documentation requirements.

Why do so many buyers end up overpaying or, worse, purchasing the wrong specification? The answer usually comes down to comparing nominal sizes without accounting for pressure class and standard. Think of it like buying a bolt: the nominal diameter alone tells you almost nothing without knowing the thread pitch and tensile grade.

Carbon steel pipe fittings price as a category also includes elbows, tees, and reducers, but flanges represent the highest-value and most specification-sensitive segment of that category — which is why a dedicated price guide is essential for any serious procurement effort.

Common flange types in the Indonesian market

Before examining harga flange carbon steel in detail, it helps to understand the five main types available from industrial flange suppliers in Jakarta, Surabaya, and Batam:

• Weld Neck (WN) flange — Features a long tapered hub welded to the pipe. The preferred choice for high-pressure and high-temperature applications in oil, gas, and petrochemical systems. Material must fully match the pipe specification.
• Slip-On (SO) flange — Slides over the pipe and is fillet-welded both inside and outside. Easier to install and approximately 35–45% cheaper than Weld Neck equivalents. Widely used in water treatment and low-pressure utility lines.
• Blind flange — A solid disc used to close off the end of a pipe run or a pressure vessel nozzle. Frequently used in chemical and refinery maintenance. Blind flanges carry significant structural load under pressure, so under-specification is a real safety risk.
• Socket Weld (SW) flange — Designed for small-bore, high-pressure pipe (typically ½ inch to 2 inches). The pipe inserts into a recessed socket and is fillet-welded at the hub. Common in hydraulic and chemical injection lines.
• Plate / Flat Face (FF) flange — The most economical option, typically used in low-pressure, non-critical service. Often seen in irrigation and general water piping. Not suitable for Class 300 or above.

Key material grades: ASTM A105 vs A516 vs Q235

Material grade is the single most important variable in carbon steel flange price and performance. ASTM A105 is the standard forged carbon steel grade for ambient and moderate-temperature service — it is the dominant material in Indonesian oil and gas procurement. A516 Grade 70 is a pressure vessel plate material sometimes used for custom flanges in low-temperature service. Q235, a Chinese structural steel equivalent to SS400, is frequently offered by low-cost importers and is technically not equivalent to A105 for pressure service — despite being visually indistinguishable. Actual testing in multiple procurement audits has confirmed that Q235 flanges can fail hydrostatic tests at pressures where A105 holds comfortably.

Price table by flange type and size (Q1 2026)

The table below provides indicative market price ranges for carbon steel flanges in Indonesia as of Q1 2026, sourced from distributors in Jakarta (Glodok/Kapuk) and Surabaya (Rungkut industrial area). All prices are per piece, exclude VAT 11%, and assume standard ASTM A105 material. Weld Neck flanges are priced separately from Slip-On due to the consistent 35–45% premium. Exchange rate basis: USD 1 = Rp 16,200.

*Indicative market ranges, Q1 2026. ASTM A105 material. VAT 11% not included. Prices may vary ±15% based on order quantity and supplier location.

JIS 10K/20K pricing vs ANSI B16.5

JIS-standard flanges (B2220 10K and 20K) remain common on older Indonesian industrial installations, particularly in water treatment plants built before 2000 and in paper mill systems that followed Japanese EPC contractors. In real case comparisons from Surabaya suppliers, a 4-inch JIS 10K slip-on flange in A105 typically runs 5–12% cheaper than its ANSI Class 150 counterpart at the same nominal size — largely because the JIS bolt circle diameter is smaller, meaning less material per piece. However, mixing JIS and ANSI flanges in the same piping loop creates misaligned bolt patterns, a costly mistake during turnaround maintenance. The steel flange cost saving is real but only justified when the entire system follows one standard consistently.

Wholesale flange price vs retail unit pricing

Wholesale flange price typically applies to orders of 50 pieces or more per specification. At that volume, Jakarta distributors routinely offer 8–18% discounts off the list prices shown above. For project procurement exceeding 200 pieces of a single spec, some steel flange manufacturers in Indonesia — particularly those in Cikarang and Gresik — provide direct-factory pricing that can reduce the flange price per unit by up to 25%. Of course, lead time may extend to 3–6 weeks for domestic production versus 1–2 weeks for import stock.

Pressure class comparison: 150# to 900# explained

Pressure class — also called pressure rating or pound rating — is the most technically misunderstood variable in carbon steel flange procurement in Indonesia. Class 150# does not mean the flange handles 150 PSI. It means the flange meets a specific pressure-temperature rating curve defined in ASME B16.5, with maximum allowable pressure varying by temperature.

Which class is right for your application?

In Indonesian oil and gas (migas) projects, Class 600# and 900# dominate upstream and midstream pipelines. Water treatment (PDAM/industrial cooling) almost exclusively uses Class 150#. Chemical plants handling corrosive or high-temperature media typically specify Class 300# as a minimum — even for relatively low operating pressures — to maintain safety margins during upset conditions. Using Class 150# in a steam system above 230°C is not just poor engineering; it violates Peraturan Menteri ESDM safety provisions for pressure equipment.

JIS K equivalent: 10K and 20K pressure ratings

For JIS-standard systems, the equivalent pressure ratings are 10K (approximately Class 150#) and 20K (approximately Class 300#). The "K" notation refers to kgf/cm², so 10K = 10 kgf/cm² ≈ 9.8 bar working pressure at ambient temperature. These are widely used in Japanese-contractor-built plants across Kalimantan, Riau, and East Java. Carbon steel valve and flange price lists from local distributors almost always include both ANSI and JIS options side by side for sizes up to 10 inches.

Standards guide: ANSI B16.5 vs JIS B2220 vs DIN PN16

Selecting the wrong standard is the costliest mistake in flange procurement. It is also surprisingly common — especially on brownfield projects where existing flanges follow one standard and replacement stock follows another. All three bolts pass through the flange, but the bolt circles do not align. The pipes do not mate. The shutdown extends. The project manager is not happy.

ANSI/ASME B16.5 — the dominant standard for most projects

ANSI B16.5 governs flanges from ½ inch to 24 inches NPS (Nominal Pipe Size) across seven pressure classes (150# through 2500#). It is the default standard specified in most EPC contracts for Indonesian oil, gas, and petrochemical projects — including those under Pertamina, Medco, and contractor frameworks following API or ASME codes. ASTM A105 flange price under B16.5 is what most of this guide's pricing data reflects.

JIS B2220 — legacy and water sector applications

JIS B2220 defines flanges in 5K, 10K, 16K, 20K, and 30K ratings. In Indonesia, 10K and 20K are by far the most common. This standard prevails in PDAM (regional water utility) infrastructure, older Pertamina refineries built with Japanese technology, and pulp and paper mills across Sumatra. Flange specification price comparisons between JIS and ANSI must account for different bolt circle diameters, face dimensions, and bolt counts — not just nominal size.

DIN PN16 — European projects and select chemical plants

DIN flanges follow PN (Pressure Nominal) ratings: PN6, PN10, PN16, PN25, PN40. PN16 is roughly equivalent to Class 150# in pressure capacity at ambient temperature. DIN flanges appear in Indonesian chemical and pharmaceutical plants built by European contractors, as well as in some PLTU (coal power) systems using European boiler technology. Carbon steel piping accessories cost under DIN standards is generally 5–10% higher than ANSI equivalents in the Indonesian market, because local stock availability is lower and most DIN-spec items are imported from Germany or China.

"Mixing ANSI and DIN flanges in a single piping system — even accidentally — creates incompatible bolt patterns that cannot be resolved by gasket substitution alone. Procurement teams must establish a single standard per project and enforce it at the purchase order level, not the inspection stage." — Industry consensus among piping engineers across multiple Indonesian EPC projects, 2026 data.

Certification and material documents: what to demand from suppliers

In industrial procurement — especially for oil, gas, chemical, and power generation applications — the documentation accompanying a flange is as important as the flange itself. Actual inspection audits have found that up to 30% of low-price carbon steel flanges sold in secondary markets in Indonesia lack traceable mill certificates, which means they cannot legally be installed in pressure systems under SNI 13-3564 or ASME Section I/VIII compliance requirements.

Mandatory documents for industrial-grade procurement

1. Mill Test Certificate (MTC / MTR) — Confirms the chemical composition and mechanical properties (tensile strength, yield strength, elongation) of the specific heat (batch) of steel used. Must include the heat number traceable to the specific piece.
2. Heat number marking — Each flange must carry a stamped or stenciled heat number that matches the MTC. Without this, traceability is broken and the piece is non-conforming.
3. ASTM compliance declaration — Specifically ASTM A105 for forged carbon steel flanges. The certificate must state the ASTM designation, grade, and test results confirming compliance.
4. Dimensional inspection report — Confirms that the flange face diameter, bolt circle, bore, and thickness meet the applicable standard (B16.5, JIS B2220, or DIN).
5. Third-party inspection (TPI) report — Required by most major operators (Pertamina, PLN, and international IOCs). Common TPI bodies include SGS, Bureau Veritas, and Sucofindo (locally accredited).
6. TKDN certificate — Since 2024, Indonesian government projects under APBN/APBD procurement increasingly require TKDN (Tingkat Komponen Dalam Negeri) certificates confirming local content percentage. Domestically manufactured flanges carry a TKDN advantage in government tenders.

Red flags when evaluating suppliers

When a supplier cannot provide an original MTC within 24 hours of inquiry, that is a warning sign. Similarly, certificates that show a generic heat number shared across hundreds of pieces (rather than a specific batch heat) are almost certainly reproductions, not originals. The pipe connection component cost may look attractive on paper, but the liability exposure from a non-certified flange failure in a pressure system far exceeds any procurement savings. Steel flange manufacturers in Indonesia who operate to ISO 9001 and carry PED (Pressure Equipment Directive) or equivalent certification can generally be assumed to have robust documentation systems.

Flange weight chart: logistics and shipping cost reference

Flange weight directly determines freight cost — both domestic trucking (per-kilogram rates from Jakarta to Kalimantan, for instance) and import customs duties (calculated on CIF weight). A project requiring 500 pieces of 10-inch Weld Neck flanges in Class 600# can easily represent 4–6 metric tons of freight weight. Getting this wrong in a logistics budget is not a minor rounding error.

*Approximate weights per ASME B16.5 tables. Slip-On flanges are 15–25% lighter than Weld Neck at equivalent size and class. Blind flanges are 20–35% heavier than Slip-On.

Using weight data for freight budgeting

A practical formula used by logistics teams in Indonesian industrial projects: multiply total piece count × average weight (kg) × domestic freight rate (typically Rp 1,500–2,500/kg for Java inter-city, Rp 3,500–6,000/kg for inter-island to Kalimantan or Papua). For a 300-piece order of 6-inch Class 300# Weld Neck flanges, that is approximately 4,200 kg — translating to Rp 14.7 million in freight cost to Balikpapan at Rp 3,500/kg. This figure is often excluded from first-round supplier quotations and catches procurement teams off guard.

Key factors that affect carbon steel flange price

Experienced buyers know that the flange specification price on a supplier's quote sheet is just the starting point. Several systemic factors drive the final landed cost — and understanding them is the difference between a well-managed procurement and a budget overrun.

Material cost and global steel market movements

Carbon steel pipe fittings price — including flanges — tracks global hot-rolled coil and billet prices with a 4–8 week lag. In Q1 2026, Chinese steel export prices remained subdued due to domestic overcapacity, keeping imported flange prices competitive. However, Indonesia's TKDN policy pressure and anti-dumping review processes have introduced unpredictability into import pricing. Domestic steel flange manufacturers have responded by investing in forging capacity, narrowing the price gap versus imports to roughly 8–15% on standard A105 grades.

Certification premium and what it actually costs

A certified ASTM A105 flange with full MTC and TPI documentation typically commands a 15–30% premium over a non-certified equivalent of the same nominal specification. Is that premium worth paying? For utility water lines in non-critical service — perhaps not always. For oil and gas or chemical process lines subject to regulatory inspection — there is simply no choice. Flange material cost Indonesia effectively bifurcates into two markets: certified industrial supply and uncertified general trade, and mixing the two in a single BOM (Bill of Materials) is an audit risk.

2026 trends: green procurement and TKDN

Two converging trends are reshaping the carbon steel valve and flange price landscape in Indonesia in 2026. Green procurement requirements — where EPC contractors must submit Environmental Product Declarations (EPDs) alongside material certificates — are adding documentation overhead that increases per-unit transaction costs by an estimated 3–7%. Simultaneously, tightening TKDN thresholds for government-funded infrastructure projects are redirecting demand toward domestic steel flange manufacturers, which is gradually building scale and competitiveness in the local industry. The net effect: imported flange pricing has become less predictable, while domestic-sourced pricing has become more competitive at standard grades.

Summary and procurement recommendations

Navigating harga flange carbon steel in Indonesia requires more than asking for a price per piece. The most cost-effective procurement strategy combines three disciplines: precise specification (type, pressure class, and applicable standard defined before any RFQ is issued); documentation discipline (MTR, heat number, ASTM compliance, and TPI as non-negotiable requirements); and total landed cost calculation (unit price + freight based on weight data + VAT + any certification inspection fee).

The price tables in this guide reflect Q1 2026 market ranges from Jakarta and Surabaya distributors. Use them as a benchmark — not as a fixed target. If a supplier's price is more than 20% below the lower end of the applicable range, ask why. There is almost always a reason, and it is rarely favorable to the buyer. Carbon steel flange price intelligence, used properly, is a procurement advantage. Used carelessly, it is a liability.