·Shanghai GM recalled design defects have nothing to do with Chinese manufacturing
Due to the ignition switch issue, General Motors recently announced in North America that it has recalled more than 3.4 million vehicles worldwide. According to media reports, the supplier of spare parts for the ignition switch is from China and is produced by Dalian Alps Electronics Co., Ltd. For a time, the credibility of "Made in China" was once again seriously questioned. In this regard, Shanghai General Motors related person said on the 27th that the GM recall and "Made in China" have nothing to do with the original design flaws of the vehicle ignition switch. It is understood that because the North American recall document requires the mention of all system sub-parts suppliers, GM recalled the document mentioning the recall of the model ignition switch supplier Dalian Alps Electronics Co., Ltd., which triggered foreign media reports. Manhole covers are used to cover roads or deep wells in homes to prevent people or objects from falling. [1] According to material, it can be divided into metal manhole cover, high-strength fiber cement concrete manhole cover, resin manhole cover and so on. Generally round. Can be used in green belts, sidewalks, motorway, docks, alleys, etc. Recessed Manhole Cover,Sewer Covers Drain Covers,Sewer Cover,Manhole Cover Sizes Jieyang Xinxin Industry and Trade Co., Ltd. , https://www.gdxxgm.com
Technical Parameters
Technical parameters Test load: heavy 400KN, general 250KN, light 125KN [1]
Bending strength: average 22MPa impact strength: average 10J / m2
Water absorption rate: 1%
Acid resistance: sample at 20%
Soak in sulfuric acid solution for 48h
No corrosion on the surface, 1% quality loss
Performance characteristics
1. High strength: Magnesite inspection has high compressive, bending and impact strength, and toughness. After long-term use, the product will not be crushed and damaged, which can completely prevent the "urban black hole" accident.
2. Beautiful appearance: The surface pattern design of magnesite inspection manhole cover is exquisite, the color is adjustable, and it can beautify the urban environment.
3. Easy to use and light weight: The product weighs only about one third of cast iron, which is convenient for transportation, installation and repair, which greatly reduces labor intensity.
4. Anti-theft: Magnesite inspection manhole cover has no recovery value and is natural anti-theft; according to customer requirements, a lock structure is provided to prevent theft of property in the well.
5. Strong weather resistance: Magnesite inspection manhole cover can be used normally in the environment of -50 ℃ ~ + 300 ℃ through scientific formula, advanced technology and perfect technical equipment.
6, acid and alkali resistance, corrosion resistance, wear resistance, rolling resistance of vehicles, long service life.
Distinguish by material
Can be divided into 4 categories
A. Metal manhole cover: cast iron, ductile iron, bronze manhole cover, etc .;
B. High-strength steel fiber cement concrete manhole cover (cement-based composite material);
C. Recycled resin manhole cover (recycled resin-based composite material);
D. Polymer-based composite inspection manhole covers, etc.
Differentiate by shape
Generally divided into circular and square.
In terms of road management in urban areas, a circular shape is generally adopted because the circular manhole cover is not easy to tilt, which can better protect the safety of pedestrians and vehicles.
Squares are generally used in rural areas and cable wells to better prevent the ingress of liquids such as rainwater.