Tire steel belts

ASTM 1070 characterizes steel tire cord and tire bead wire. These materials are considered high carbon steei. Steei beits have carbon content between 0.67 and 0.73% whiie bead wire has a minimum of 0.60% carbon. Also, tire steel belts and tire bead wire possess between 0.40 to 0.70% manganese. 

Tire Cord. Melamine resins are also used to improve the adhesion of mbber to reinforcing cord in tires. Textile cord is normally coated with a latex dip solution composed of a vinylpyridine—styrene—butadiene latex mbber containing resorcinol—formaldehyde resin.. The dip coat is cured prior to use. The dip coat improves the adhesion of the textile cord to mbber. Further improvement in adhesion is provided by adding resorcinol and hexa(methoxymethyl) melamine [3089-11 -0] (HMMM) to the mbber compound which is in contact with the textile cord. The HMMM resin and resorcinol cross-link during mbber vulcanization and cure to form an interpenetrating polymer within the mbber matrix which strengthens or reinforces the mbber and increases adhesion to the textile cord. Brass-coated steel cord is also widely used in tires for reinforcement. Steel belts and bead wire are common apphcations. Again, HMMM resins and resorcinol [108-46-3] are used in the mbber compound which is in contact with the steel cord to reinforce the mbber and increase the adhesion of the mbber to the steel cord. This use of melamine resins is described in the patent Hterature (49). 

Whole tires have been pyrolyzed in an experimental semifluidized-bed reactor (27). The tires are pyrolyzed on a grate that tilts to discharge the steel belt and bead wire. The pyrolysis of whole tires eliminates shredding and grinding costs. 

Insoluble Sulfur. In natural mbber compounds, insoluble sulfur is used for adhesion to brass-coated wire, a necessary component in steel-belted radial tires. The adhesion of mbber to the brass-plated steel cord during vulcanization improves with high sulfur levels ( 3.5%). Ordinary rhombic sulfur blooms at this dose level. Crystals of sulfur on the surface to be bonded destroy building tack and lead to premature failure of the tire. Rubber mixtures containing insoluble sulfur must be kept cool (<100°C) or the amorphous polymeric form converts to rhombic crystals. 

The role of the mbber compounds which are used ia these basic components is threefold (/) to provide the coatact area betweea the vehicle and the surface (2) to provide the cohesive material that holds the tire together such that it acts as an iategral unit and (J) to provide protection for the ultimate strengthbeating components, ie, the textiles, steel beads, and steel breakers ia steel belted radial tires. 

Component Parts. Desired properties ia the components of a radial steel belted passeager car tire (PCT) are as follows. 

The carcass ply/pHes coat compouad fuactioas are basically the same as the steel breaker compouad. Normally ia the steel belted PCT the ply is textile cord of polyester or rayoa fabrics which are soft and flexible. The tmck radial steel tire normally uses a steel cord ply. Earthmover tires are of two basic constmctions, ie, radial usiag steel and bias usiag textiles (see Tire cords). 

Introduced successfully for tires in 1967, glass fibers had properties that made them very attractive for use in tires (5,8). The britdeness of glass fibers, however, imposed some limitations on the final tine cord properties because of the requirement that each fiber be individually coated with a mbbery adhesive to avoid interfilament damage during fabrication and use. This additional treatment step is introduced at the fiber manufacturing stage. For several years fiber glass was used extensively in bias-belted and radial tires, but was ultimately replaced by steel belts in radial tires. 

An example that shows that the cohesive strength of a material is less than that of the adhesional strength of the interface is that of the nominal 50,000 mile steel belted radial tire. It is a simple calculation to show that, on average, a tire leaves a monolayer of rubber particles on the road every time it makes a rotation. In essence, the strength of the adhesional bonding between the road and the tire is greater than that of the rubber within the tire. 

The effect can be seen in Figure 26.75 which shows the results obtained with the two-wheeled trailer discussed above. Tire group A was a re-treaded bias tire group B a commercial steel-belted radial ply tire. When one tire of each group was mounted on the axle of the trailer for equal set slip angles, the direction of the tow bar adjusted itself in such a way that the tires run under the same... 

While a new tire may have excellent resistance to crack initiation and propagation between the steel belts, an aged tire of the exact same construction can exhibit dramatically reduced crack growth resistance, which in some cases may contribute to tire failure. To further underscore the point, the United States National Highway Traffic Safety Administration (NHTSA) determined that tire aging was a main contributor to the Firestone Wilderness AT tire recall [1]. Figure 34.1 shows the failure rate of Wilderness AT tires as a function of tire age (determined from date of tire manufacture). 

FIGURE 34.2 Diagram of steel belt portions of a tire. 

Vinylpyridine is used in the terpolymer latex component of tire cord dips to improve the bonding of textile to rubber. Rubber hres built with steel cord, however, do not require vinylpyridine latex-based adhesives for the steel belt, Therefore, the consumption of vinylpvridines may be affected in the future,... 

What do bamboo stalks, mud bricks, steel-belted radial tires, fiberglass fishing rods, reinforced concrete, and the heat tiles on a space shuttle have in common The answer is that these materials are all composites. A composite is a material consisting of two or more components with overall properties different from and superior to either or any one of the individual components. For example, many pleasure boats today have hulls made of a composite material called reinforced plastic that contains glass, plastic, carbon, or some other type of fiber embedded in plastic. The composite material is stronger, more durable, and less dense than the fibers or plastics of which it is made. 

Pyrolysis produces three principal products - pyrolytic gas, oil, and char. Char is a fine particulate composed of carbon black, ash, and other inorganic materials, such as zinc oxide, carbonates, and silicates. Other by-products of pyrolysis may include steel (from steel-belted radial tires), rayon, cotton, or nylon fibers from tire cords, depending on the type of tire used. 

The N 300 series is characterized by a wide variety of rubber blacks, covering about 10 different types. As mentioned above, fme-particle active blacks are used for rubber components that need to withstand significant levels of mechanical stress, e.g. tire treads. Semi-active blacks, on the other hand, are used in the tire carcass but also in technical rubber components, from screen and door seals to floor mats. Tires also contain other special carbon blacks, for instance, so-called adhesion blacks for improving radial steel belt adhesion, conductive blacks or inactive blacks for higher filler load rates [4.26]. 

The air in a steel-belted tire is at a gauge pressure of 29.8 psi at a temperature of 20°C. After the tire is driven fast on a hot road, the temperature in the tire is 48°C. What is the tire s new gauge pressure ... 

With waste rubber goods, as with nonsegregated plastic wastes, it is possible to simply burn the rubber and regain the considerable fuel value. Whole scrap tires have been burned in cement kilns, for example, to obtain a proportionate saving in the usual oil or gas fuel supply used in these operations. At the extremely high kiln temperatures the combustion is complete and any steel belts or beading are incorporated into the cement klinker without problems. 

Given that Harvey s flat tire is a steel-belted tire, explain how the ignition of the gas mixture might have been triggered. (A steel-belted tire has two belts of steel wire for outer reinforcement and two belts of polyester cord for inner reinforcement.)... 

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