Products Description

Our carbon steel plate flange is made according to the ASTM A105 standard, and the chemical composition ratio takes into account both strength and processability: the carbon content is 0.3-0.35%, manganese is 0.6-1.05%, and there is a little silicon. As a result, its tensile strength can reach 480-650 MPa, and the elongation is 23%. It is suitable for medium and low pressure systems such as water pipelines, HVAC and general industrial occasions.

Wholesale people think it is cost-effective - 35% cheaper than stainless steel flanges, but it can handle most non-corrosive scenes. We have done bending tests according to the ASTM E290 standard, and it did not crack even when bent to 180 degrees. Even if customers install it in a narrow space, they don't have to worry about it breaking.

Factory Processing

We offer two key finishes: oiled (to prevent rust during storage) and sandblasted (Sa 2.5 per ISO 8501-1) for better paint adhesion in outdoor settings. The sandblasted surface has a roughness of 50-80μm, which helps paint stick 50% longer than untreated surfaces.

Our CNC machining ensures precise dimensions: flange thickness tolerance is ±0.5mm, and the bolt circle diameter stays within ±0.3mm (ASME B16.5). We also provide custom drilling for non-standard bolt patterns, with a turnaround time of 48 hours for small batches, and every flange gets a pressure test (1.5x working pressure, per ASTM B16.5) before shipping.

Production Strength

As a Chinese manufacturer with 10 years supplying European construction and utility markets, we run 8 plate rolling lines and 6 CNC cutting machines, with an annual capacity of 12,000 tons. Our raw plates come from mills certified to ISO 9001, and each batch undergoes a hardness test (Rockwell B 65-80, ASTM E18) to ensure consistency.

We keep 600-800 tons in stock at our Tianjin warehouse, covering sizes from 4" to 36" in diameter and thicknesses 10mm to 50mm. Inventory updates twice daily on our website, and FOB Tianjin shipments for in-stock Carbon Steel Plate Flange leave within 5 days-handy for keeping your customers' projects on schedule.

Factory Commitments

Orders over 80 tons get a 5.5% discount, plus free sandblasting and 15% of sea freight.

Here's our guarantee: If any flange has dimensional errors exceeding ±1mm or fails to meet ASTM A105 tensile strength standards, we'll replace it within 4 days and cover all shipping costs. For repeat customers, we offer a 3% loyalty discount on top of bulk pricing, and we lock prices for 25 days on confirmed orders to avoid market surprises.

Product Ingredients

Element	Q235	20#	A105	A36
C	≤0.22%	0.17-0.24%	0.3-0.35%	≤0.25%
Si	≤0.35%	0.17-0.37%	≤0.35%	≤0.40%
Mn	0.30-0.65%	0.35-0.65%	0.60-1.05%	0.80-1.20%
P	≤0.045%	≤0.035%	≤0.035%	≤0.040%
S	≤0.045%	≤0.035%	≤0.035%	≤0.050%
Fe	Balance	Balance	Balance	Balance

Q235: China's national standard carbon structural steel, with good plasticity and weldability, commonly used in construction, structural parts, etc.
20#: China's high-quality carbon structural steel, with medium carbon content and excellent toughness, suitable for manufacturing pipes, bolts, etc.
A105: American ASTM standard carbon steel forging brand, mainly used for high-pressure pipeline flanges, valves, etc., with balanced strength and toughness.
A36: American ASTM standard carbon structural steel, with similar performance to Q235, widely used in bridges, machinery manufacturing and other fields

Product Parameters

Parameter	Details
Product Name	Carbon Steel Plate Flange
Material	Carbon steel (e.g., Q235B, A36, 20#)
Tensile Strength	375-560MPa
Pressure Rating	Class 150-300
Nominal Diameter	DN15-DN2000 (1/2"-80")
Seal Face Type	Flat Face (FF), Raised Face (RF)
Standards Compliance	GB/T 9112-2010, ASME B16.5 (for export)

Material Performance Comparison

Material	Tensile Strength (MPa)	Corrosion Resistance	Cost	Application Temp
Q235B Carbon Steel	375-500	General (needs coating)	Low	-20°C to 300°C
A36 Carbon Steel	400-550	Similar to Q235B	Low	-30°C to 350°C
304 Stainless Steel	515-620	Excellent (rust-resistant)	High	-270°C to 870°C

Service and Customization

Service Type	Options	Lead Time
Custom Sizing	Non-standard diameter, thickness (6-100mm)	7-15 days
Surface Treatment	Painting, galvanizing, sandblasting	2-3 days
Certifications	MTR, ISO 9001, Pressure test report	Included
Order Flexibility	MOQ 1 piece, urgent orders (5-7 days)	7-15 days

Product Application and Selection

Industry	Recommended Pressure Rating	Key Advantages
Municipal Engineering	Class 150	Low cost, easy installation
Water Treatment	Class 150-300	Suitable for water/sewage
HVAC Systems	Class 150	Suitable for low-pressure pipelines
General Industry	Class 150-300	For non-corrosive media