Views: 2 Author: Site Editor Publish Time: 2025-08-15 Origin: Site
A regular customer from Singapore has sent a procurement request, planning to purchase 20 pcs Class 300 blind flange with a delivery time of 7 days.
Material Standard: ASTM A350 LF2 low-temperature steel
Size : DN750
Pressure:Class 300
Production Standard: ASME B16.47A
Sealing Surface Type: RF
From the perspective of delivery time, the customer urgently needs to use this blind flanges. Although the quantity of this order is small, we are well aware of the urgency of this order of Class300 blind flange. Therefore, we immediately arranged production upon receiving the order, and the procurement department tracked the production progress throughout the process and provided timely feedback to the customer to ensure delivery within the deadline. Regardless of the amount or quantity of the order, treating each order with a rigorous attitude has been our business philosophy that Shanghai Zhengcheng has adhered to for many years. Before each flange leaves the factory, the quality inspection department will conduct a comprehensive dimensional inspection (including outer diameter, thickness, sealing surface tolerance, etc.) in accordance with ASME B16.47A standard, and retain the inspection report to ensure that the product meets the customer's usage requirements.
Inspection of DN750 Class 300 Blind Flange
Due to the fact that low-temperature steel is also a material that is prone to rusting, we will spray anti rust oil on the surface of each flange before packaging to prevent rusting and affect the aesthetic appearance of the product. Considering the product characteristics of a single weight of 700KG, we will adopt a packaging method of wooden pallets, integral wrapped plastic film, and top covered wooden boards to effectively prevent moisture and collision, ensuring the safety of the products during transportation.
Package of Class 300 Blind Flange
Blind flange is a type of flange without a central through-hole, similar in appearance to a regular flange, usually with bolt holes, which can be connected to the flange or equipment at the end of the pipeline through bolts, and sealed with a sealing gasket in the middle. Its structure is simple but has strong pressure bearing capacity. At the same time, it is installed through the combination of sealing surfaces and gaskets to seal the pipeline.
According to different classification criteria, blind flanges can be classified into various types.
Divided by pressure level, there are different levels such as Class150, Class300, Class600, etc. Blind flanges with different pressure levels are suitable for pipeline systems in different pressure ranges. For example, Class300 blind flanges are suitable for medium and high pressure conditions.
According to material classification, common types include carbon steel, stainless steel, low-temperature steel, etc. For example, blind flanges made of ASTM A350 LF2 low-temperature steel material are suitable for low-temperature environments.
According to the sealing surface form, there are protruding surface (RF), concave convex surface (MFM), tenon groove surface (TG), etc. Different sealing surface forms need to be matched with corresponding gaskets to achieve good sealing effect. For example, blind flange of RF sealing surface is widely used in industry with stable sealing performance.
Sealing Surface | 凸面(RF), 平面(FF) |
Dimension | 1/2"- 48"/ DN15 - DN1200 |
Pressure | Class 150, 300, 600, 900, 1500, 2500 |
Standard | ASME B16.5，ASME B16.47 A/B |
Carbon Steel | ASTM A105, ASTM A350 LF2,ASTM A694 F42 / 46 / 56 / 60 / 65 |
Alloy Steel | ASTM A182 F11 / 12 / 5 / 9 / 91 / 92 |
Stainless Steel | ASTM A182 F304/304L/304H, 316/316L, 310S, 317,347,904L |
Duplex Stainless Steel | ASTM A182 F51, F53, F44 |
| Nominal Pipe Size | A | C | G | H | I | J | Weight | |
| inch | mm | mm | mm | mm | Holes | mm | mm | kg / piece |
| 1/2 | 21.3 | 95.2 | 14.2 | 35.1 | 4 | 15.7 | 66.55 | 0.64 |
| 3/4 | 26.7 | 117.3 | 15.7 | 42.9 | 4 | 19 | 82.5 | 1.11 |
| 1 | 33.4 | 123.9 | 17.5 | 50.8 | 4 | 19 | 88.9 | 1.39 |
| 11/4 | 42.2 | 133.3 | 19 | 63.5 | 4 | 19 | 98.5 | 1.79 |
| 11/2 | 48.3 | 155.4 | 20.6 | 73.15 | 4 | 22.3 | 114.3 | 2.66 |
| 2 | 60.3 | 165. 1 | 22.3 | 91.9 | 8 | 19. 10 | 127 | 3.18 |
| 21/2 | 73.0 | 190.5 | 25.4 | 104.6 | 8 | 22.3 | 1.493 | 4.85 |
| 3 | 88.9 | 209.5 | 28.4 | 127 | 8 | 22.3 | 168.1 | 6.81 |
| 31/2 | 101.6 | 228.6 | 30.2 | 139.7 | 8 | 22.3 | 184.1 | 8.71 |
| 4 | 114.3 | 254 | 31.7 | 157.2 | 8 | 22.3 | 200.1 | 11.5 |
| 5 | 141.3 | 279.4 | 35 | 185.7 | 8 | 22.3 | 234.9 | 15.6 |
| 6 | 168.3 | 317.5 | 36.5 | 215.9 | 12 | 22.3 | 269.7 | 20.9 |
| 8 | 219. 1 | 381 | 41.10 | 269.7 | 12 | 25.4 | 330.2 | 34.3 |
| 10 | 273.0 | 444.5 | 47.7 | 323.9 | 16 | 28.4 | 387.3 | 53.3 |
| 12 | 323.8 | 520.7 | 50.8 | 381 | 16 | 31.7 | 450.8 | 78.8 |
| 14 | 355.6 | 584.2 | 53.8 | 412.8 | 20 | 31.7 | 514.3 | 105 |
| 16 | 406.4 | 647.7 | 57.15 | 469.9 | 20 | 35 | 571.5 | 137 |
| 18 | 457.2 | 711.2 | 60.45 | 533.4 | 24 | 35 | 628.6 | 175 |
| 20 | 508.0 | 774.7 | 63.5 | 584.2 | 24 | 35 | 685.8 | 221 |
| 24 | 609.6 | 914.4 | 69.85 | 692.2 | 24 | 41. 10 | 812.8 | 339 |
Blind flange can be classified according to pressure levels class 150lb，class 300lb，class 400lb，class 600lb，class 900lb，class 1500lb，class2500lb, To view other product parameters, please click on the following link:
ASTM A350 LF2 is a carbon steel forging material widely used in low-temperature environments. With excellent low-temperature toughness, stable mechanical properties, and good processability, it occupies an important position in the industrial field, especially in the manufacturing of pressure pipelines and pressure vessels.
The chemical composition design of LF2 material balances strength and toughness:
Controlling the carbon (C) content at a low level can reduce the adverse effects of carbide precipitation on low-temperature toughness; Manganese (Mn), as the main alloying element , can significantly improve the strength and hardenability of steel; Simultaneously limiting the content of harmful elements such as sulfur and phosphorus , reducing the material's tendency towards brittleness, and ensuring welding performance and processing capability.
| CHEMICAL | LIMITS | C | Mn | P | S | Si | Cu | Ni | Cr | Mo | V | Nb |
| ASTM A350 LF2 | MIN | 0.60 | 0.15 | |||||||||
| MAX | 0.30 | 1.35 | 0.035 | 0.040 | 0.35 | 0.40 | 0.40 | 0.30 | 0.12 | 0.08 | 0.02 |
After normalizing or normalizing+tempering treatment, LF2 material has stable mechanical properties:
The tensile strength can reach 485-655MPa, meeting the strength requirements of medium and high pressure working conditions;
The yield strength shall not be less than 250MPa, ensuring that plastic deformation is not easily caused when subjected to load;
Elongation rate≥22%, exhibiting good plasticity and able to adapt to a certain degree of deformation requirements.
| MATERIAL | T.S (MPA) | Y.S (MPA) | EL % | R/A % | HARDNESS |
| ASTM A350 LF2 | 485-655 | 250 min | 22 min | 30 min | 197 max |
Low temperature toughness is the core competitiveness of LF2 material. Through the Charpy V-notch impact test, it has been verified that its impact energy (KV2) can usually reach over 20J at -46 ℃, which is much higher than that of ordinary carbon steel, effectively avoiding the risk of brittle fracture at low temperatures. This is also the key reason why it is widely used in low-temperature pipeline systems.
| Impacet Test Temerature at -50°F[-46℃] | ||||||
| Size, mm | Average/min, ft.lbs[J] | One Specimen Only of a Set,ft.lbs[J] | ||||
| 10X10 | 15[20] | 12[16] | ||||
Petrochemical and Natural Gas Industries
Low Temperature Engineering Field
Food Processing Industries
Pipeline
Power Industries
Ship Building Industries
Paper Industries
Cement Industries
Chemical Industries
