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Allowable stress for mild steel?
That really depends on the type of stainless steel and how it is conditioned. For example 300 series steels that are annealed have a yield strength of 30,000 psi and a tensile strength of 80,000 psi. But if cold worked these increase to 65,000 psi and 125,000 psi, respectively, and even higher depending on method. For high strength stainless steels such as A286 or 17-4 PH, tensile strengths over 160,000 psi are realized.
Why concrete cover is important?
The most important reason for "Depth of Cover" requirements, is to afford protection to the steel reinforcement embedded in the concrete. Certain tension, compression and bending moments also play a role, when the structural engineer designs for loads of the intended use, however the need to prevent corrosion [rust] from forming on the steel is the primary objective. New concrete has pH of 13-13.2 when placed. This high pH forms a "Passivating Layer" on the steel. The deeper placement of the steel [ Cover ] delays the degradation of the pH to a level that supports and fosters formation of corrosion cells. Chloride ions [Salts] are the most common contaminates in concrete that commence a corrosive environment. At a pH of 13.2, a chloride level of 8000 ppm are needed to begin rusting steel ! When that pH drops to a level of 11.5 the chloride threshold is lowered to 70 ppm ! Drastic difference ! Rusting Re-Bar expands in size as rust forms on it's surface. This expansion swells the re-bar size to the point that the concrete surrounding the steel cracks away [spalls] and the bond is lost, weakening the concrete in tension. Now cracked or spalled, these cracks allow a new path for contaminates and moisture to enter the matrix and speed the corrosion process up significantly. This corrosion leads to unsightly rust stains, loss of designed strength and very expensive repairs to the concrete. Left to continue a complete failure will occur. Although several other conditions may contribute to the corrosion cycle, by far, Depth of Cover is the most Important. Knowledgeable structural designers and contractors should also call for a specification to "Waterproof the Concrete". Doing so will slow the loss of pH and decrease the oxygen and moisture content at the level of the steel inside. Corrosion does not occur if moisture and oxygen are not present!
What are the disadvantages of aluminum over steel as a reinforcement bar?
They are too numerous to mention! Steel embedded in concrete is protected from corrosion by the high alkali content of concrete. New concrete is 13-13.2 pH when poured. The chemical reaction that takes place between the concrete and steel forms what is called a 'Passivating Layer' on the steel. This layer, kept intact will prevent rust from occurring on the steel. Google, passivating layer and read. It is very important to keep this high pH during a concrete structures life. One way this is done is to waterproof the concrete. Aluminum doesn't share this characteristic and corrodes quite easily when placed in concrete. This why, if an Aluminum railing post is to be embedded in a concrete a core is extracted, an appropriate filler material is placed in the hole, then the Aluminum is inserted. Filler materials [usually an epoxy] isolate the Aluminum from contact with the concrete and also prevent electrical currents from flowing. If aluminum is IN the concrete, Dissimilar metal corrosion begins day one between steel and aluminum. In short order the aluminum will be a powder. Steel cost less, easier to work with and can be welded conventionally on site.
What will be the single phase voltage when pH to pH voltage is 408 v?
235.6 volts.
What pH is best for most parts of the body?
pH 7 is best because it is neutral.
What would cause the satinless steel railings in a pool to turn black?
Stainless steel railings in a pool can turn black due to exposure to high levels of chlorine or other chemicals in the water, which can cause corrosion and discoloration. Additionally, environmental factors such as saltwater and humidity can contribute to tarnishing and oxidation of the stainless steel, leading to a black appearance. Regular maintenance and cleaning with appropriate stainless steel cleaners can help prevent this issue.
Why do you inject phosphate in boiler feed water?
To control the alkalinity of boiler water which is directly related to pH control. Too alkaline will cause stainless steel to brittle while too low alkalinity will cause corrossion.
What happens to the pressure at locations moving vertically up or down a pH constant-enthalpy line?
the pressure remains the same
How do you make steel can for honey packing for export purpose?
Honey is acidic, with a pH of between 3.2 and 4.5. For this reason it is not recommended to store it in steel containers.
What is ams 5659?
this specification describes 15-5 PH corrosion resistant steel bar.
What is the lowest pH ever recorded from acid rain and where?
Wheeling, WV... During the height of steel production a acid rain pH of less than 2 was recorded. I'm not sure of the year, can anyone else find it?
What are the mechanisms of the passivation process?
Under normal conditions of pH and oxygen concentration, passivation is seen in such materials as aluminium, iron, zinc, magnesium, copper, stainless steel, titanium, and silicon. Ordinary steel can form a passivating layer in alkali environments, as rebar does in concrete. The conditions necessary for passivation are recorded in Pourbaix diagrams. The Passivation process is typically an immersion process involving nitric acid. Passivation is the process of making a material "passive" in relation to another material prior to using the materials together
Allowable stress for mild steel?
That really depends on the type of stainless steel and how it is conditioned. For example 300 series steels that are annealed have a yield strength of 30,000 psi and a tensile strength of 80,000 psi. But if cold worked these increase to 65,000 psi and 125,000 psi, respectively, and even higher depending on method. For high strength stainless steels such as A286 or 17-4 PH, tensile strengths over 160,000 psi are realized.
How do you start a search when your mother is adopted?
Department of Community Services, freedom of Information Department, Level 2, 164-174 Liverpool Road. Locked Bag 28 Ashfield NSW, Australia 1800 pH 02 97 162222
What has the author B C Syrett written?
B. C. Syrett has written: 'The effect of PH on the free-corrosion characteristics of 18% Ni (250) maraging steel in 3.5% NaCl solutions' -- subject(s): Corrosion, Hydrogen-ion concentration, Steel alloys
What is the most acidic pH 10 pH 3 pH 2 pH 6 pH 8 pH 12 pH 1 pH 75?
PH 75 is the most acid.
How do you prepare ferrous sulphate?
H2SO4 (30%-40%) added slowly to steel wool. The pH of the solution should be acidic at any given time, otherwise the ferrous ions will oxidize to the ferric state. The sulfuric acid will begin to dissolve the steel, producing hydrogen gaz.
