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Composite SMC Material data
May 13, 2021All of our composite access covers, manhole covers in round, square and rectangular, gully gratings and frames, gully tops, rain gratings, inspection Chambers, recessed access covers, Bridge Drainage and Tank Sumps etc are made of composite SMC(sheet moulding compound), SMC is Unsaturated polyester resins reinforced with glass fibers.
SMC is an abbreviation for Sheet Molding Compound, which is a high strength glass fiber reinforced thermoset,moulding material which is normally compression moulded. It combines glass fiber and unsaturated polyester/ phenolic/ Vinyl and Acrylic modified resins, fillers(Calcium carbonate), catalysts, pigments and stabilizers, release agents to produce a high strength moulding compound.
Glass reinforcement is between 10% and 60%, and glass length is between 1/2-inch and 1-inch (25mm).
Manufacture of sheet molding compounds is a continuous in-line process. The material is sheathed both top and bottom with a polyethylene or nylon plastic film to prevent auto-adhesion. The paste is spread uniformly onto the bottom film. Chopped glass fibers are randomly deposited onto the paste. The top film is introduced and the sandwich is rolled into a pre-determined thickness. The sheet is allowed to mature for 48 hours. Delivered as sheet usually 2.5-6mm and 1000-1200mm wide.
SMC is ideal for large structural components due to its high strength-to-weight ratio. SMC offers additional benefits in part design allowing localised rib reinforcement and bosses for fastening attachments and sub assemblies. Significant tooling investment and overall component cost savings result from part consolidation. With the same coefficient of thermal expansion as Steel and excellent corrosion resistance, SMC is an ideal alternative to Steel and can be used in the same fluctuating temperature environments. The main benefit however is a typical 25% weight reduction achieved at similar strength to Steel.
The heat stability, mechanical and electrical properties of SMC are key attributes to its success in a number of industries including the automotive sector where it is commonly used in painted body panels, lightweight structural panels such as bumpers, valve covers, and engine shields. SMC is also extensively used in the production of electrical enclosures, lighting, solar, shower bases, walls, and sinks.
Manufacturing process including pulping, premix, placing glass fibers, steeping and rolling etc.
All parts of our covers are used high strength of thermoset SMC composites which made by our company.
SMC—Sheet Moulding Compounds, Refers to the reinforced unsaturated glass fiber resin sheet molding compound which is mainly composed of unsaturated resin, glass fiber, filler and functional additives, is one kind of high performance composites used for compression molding.
The main components including glass fiber, unsaturated polyester resin, filler and related additives.
This material use glass fiber as reinforcing material .So the SMC material has good wear proof.
The material has good fatigue resistance and long service life.
Manufacturing process: Under the condition of high temperature and high pressure, with large hydraulic equipment one-time molding, without any steel reinforced material.
Meeting the standards of EN124:1994 and Australian Standard of AS3996-2006.
Standard rules the resistance on the material surface is 106-8 Ω. We actually adopted SMC material which surface resistance is 104-6 Ω to make the product has better antistatic performance.
SMC material has good chemical resistance (acid, alkali, salt, organic solvent, etc.), Long-term use in the environment of underground or oil gas will not result in the change of material structure or performance.
SMC material has high density and low water absorption (0.15mg). It has excellent waterproof.
By improving the mechanical properties of materials and optimizing the structural design, make the product in the process of installation and use not cause deformation, displacement and cracking phenomenon.
Thermal deformation temperature of SMC materials is greater than 200 ℃. It can be in -55℃~+150℃ for long-term use and the environment temperature changes will not affect product performance.
Test Project Name | Required Value | Test Result | Standard |
Flexural Strength(Mpa) | ≧170 | 215 | GB/T1449-2005 |
Flexural Modulus(Gpa) | ≧10.0 | 12 | |
Tensile Strength(Mpa) | ≧100 | 138 | GB/T1447-2005 |
Impact Toughness(kJ/m2) | ≧90 | 762 | GB/T1451-2005 |
Barcol Hardness | ﹥60 | 70 | GB/T3854-2005 |
Water Absorption | <0.3% | 0.09% | GB/T1462-2005 |
The Average Thermal Expansion Coefficient (/℃) | – | 11.9×10-6(20~105℃) | GB/T9979-2005 |
From above table, we can find that our SMC Properties are higher standards request on all aspects. So our SMC material used on manhole covers will have better loading capacity, fatigue resistance, impact resistance.
Item | Flex Strength MPa | Flex Mod GPa | ||||
0h | 48h | Retention(%) | 0h | 48h | Retention(%) | |
Xylene | 215 | 205 | 95.3 | 12 | 12 | 100 |
Sulfuric Acid 40% | 215 | 220 | 102.3 | 12 | 12.2 | 101.7 |
Hydroxide 10% | 215 | 210 | 97.7 | 12 | 11.8 | 98.3 |
Gasoline | 215 | 210 | 97.7 | 12 | 10.6 | 88.3 |
From the data , we can find that SMC material has the good acid , alkali, organic matter , oil and gas resistance .Covers made with this material can be widely used in the presence of chemicals,petroleum and petrochemical industries.
Test Project Name | Test Result | Standards | |
MPa | GPa | ||
Flexural Strength | Flexural Modulus | ||
(25℃) | 215 | 12 | GB/T1449-2005 |
Normal Temperature | |||
(150℃) | 152 | 7.52 | |
High Temperature | |||
(-50℃) | 238 | 12.4 | |
Low Temperature |
Covers used SMC material has a long time use between -50℃-150℃ because of its ‘good performance under the temperature more than 200℃ and low to -50℃.
Test Project Name | Required Value | Test Result | Standards |
Oh | ﹤1.0×106 | 1.0×104 | GB16413-2009 |
Surface Resistivity |
According to the China standards, the surface resistance of SMC should be less than 106Ω, which can be defined as passing the Anti-electrostatic test. Our SMC material have better Anti-electrostatic properties because of the surface resistance is 104 Ω with our special formulation and manufacturing process. This kind of covers applies in variety occasions of combustible gases. Effectively prevent the explosion caused by electrostatic.
ITEM | Test of Heat Aging | Test of Artificial Xenon Resistance | Test Standard | ||||
0h | 500h | 1000h | 0h | 500h | 1000h |
EN513-1999 PAS26:1998 Compare with the initializer . |
|
Flex Strength Mpa | 208 | 200 | 196 | 208 | 205 | 191 | FlexStrength change :<40% |
Flex Mod GPa | 11.7 | 10.8 | 11.1 | 11.7 | 12.1 | 11.5 | FlexMod change:<30% |
Above sheet shows the material has excellent weather resistance, under the long time sun and rain, it still can use long time, and the covers lifespan is up to 20 years.