Steel cold rolling, effect

Figure 8.2. Effect of carbon in steels cold-rolled 50%, or subsequently annealed, on corrosion in deaerated 0.1A/ HCI, 25°C [1], (Reproduced with permission. Copyright 1964, The Electrochemical Society.)...

As with chemical etches, developing optimum conversion coatings requires assessment of the microstructure of the steel. Correlations have been found between the microstructure of the substrate material and the nature of the phosphate films formed. Aloru et al. demonstrated that the type of phosphate crystal formed varies with the orientation of the underlying steel crystal lattice [154]. Fig. 32 illustrates the different phosphate crystal morphologies that formed on two heat-treated surfaces. The fine flake structure formed on the tempered martensite surface promotes adhesion more effectively than the knobby protrusions formed on the cold-rolled steel. 

A cylindrical steel pressure vessel (AlSl SAE 10.85, cold rolled) with a wall thickness of 0.1 in. and an inside diameter of 1 ft is subject to an internal pressure of 1,000 psia and a torque of 10,000 ft-lb (see Figure 2-30). What is the effective stress at point A in the wall What is the factor of safety in this design ... 

Assembly errors are not simply the additive effects of tolerances, but also include the relative placement of each part s center of rotation. For example, a perfectly balanced blower rotor can be assembled to a perfectly balanced shaft and yet the resultant imbalance can be high. This can happen if the rotor is balanced on a balancing shaft that fits the rotor bore within 0.5 mil (0.5 thousandths of an inch) and then is mounted on a standard cold-rolled steel shaft allowing a clearance of over 2 mils. 

Further evidence of the relative resistance of maraging steel is reproduced in Fig. 3.33 from Reference 24. Maraging steel is shown to be superior to a die steel and low alloy steel (both unidentified) in bent beam tests stressed at 75% of the yield strength in distilled water. Also shown is the beneficial effect in smooth surface tests of cold rolling. Shot peening has a similar beneficial effect . 

Many studies have shown that surface pretreatment of Fe-Cr alloys has a strong effect on the scale morphology and subsequent oxidation rate For instance, Caplan indicated that several Fe-Cr alloys show improvement in the corrosion resistance due to cold work, with greater than 16% Cr required to show the optimum benefit. Khanna and Gnanamoorthy examined the effect of cold work on 2.25%Cr-l%Mo steels at temperatures between 400°C and 950°C over 4h in 1 atm O2. They found that up to 90% reduction by cold rolling had a negligible effect on the oxidation rate up to 700°C. However, above 700°C there was a general reduction in the kinetics... 

Fig. 19.11 Effect of specimen position on corrosion in salt-spray tests specimens of cold-rolled steel, (a) 20% NaCl, (i>) synthetic sea-water...

T. Nguyen and E. Byrd, FTIR-RA spectral characteristics of epoxy coatings on cold-rolled steel effects of film thickness and angle of Incidence, Appl. Spectrosc. submit for publication, 1985. 

Metal specimens coated with the various blends were immersed in water in an accelerated test to determine the effect of high humidity. Cellulose acetate butyrate blends containing carboxylated polyesters prepared with hexahydroterephthalic acid [H(NPG), T50H(NPG)] were particularly susceptible to moisture and failed the adhesion test after immersion for only 0.5 hour similar blends containing T50I(NPG) extended with dianhydride Via or with PMDA passed the adhesion test after immersion for 16 hours. When coatings on cold-rolled steel of cellulose acetate butyrate (EAB-381-0.5) blends containing 1% of each of the... 

Figure 5. Effect of metal substrate on current cutoff. Latex stabilized by N(m-trifluoromethylbenzyl)-N-dodecyl-Fl,Fl-dimethyUimmonium chloride. = —1.64 V (A) platinum (B) cold rolled steel (C) copper (soft sheet). Curves B and C displaced 3 and 6 sec, respectively.

How effectively a DC discharge of argon could clean the cathode surface can be seen by observing the disappearance of color of the cathode, which is created by the deposition of TMS on a cold-rolled steel, by Ar discharge treatment [2]. The cathodic... 

Wang, Y, and X. Jing. 2004. Preparation of an epoxy/polyaniline composite coating and its passivation effect on cold rolled steel. Polym J Tokyo Jpn 36 (5) 374. 

It is known that conducting polymers provide beneficial protection to various kinds of metals in a corrosive environment [443-445]. Over the past decades, conducting polymers have been considered as the potential candidate for effective corrosion protection without the use of heavy metals. It was found that PPy-clay nanocomposites with low clay loading (e.g., 1.0 wt%) provided an enhanced corrosion protection effect on cold-rolled steel compared with pristine PPy [446]. Similarly, PANI-clay nanocomposites exhibited a better anticorrosion performance than conventional PANI [447]. In the... 

Figure 8.3. Effect of heat treatment of mild steel after quenching or cold rolling (70% reduction of thickness) on resistance to stress-corrosion cracking in boiling nitrate solution [15], (Reprinted with permission of ASM International. All rights reserved, www.asminterna tional.org.)...

FIG. 2—Effect of iron, nickel, and copper contaminant levels on ASTM B 117 salt spray corrosion rates In AZ91 alloy versus cold-rolled steel and 380 die cast aluminum [10,19]. 

High-purity AZ91 clearly possesses lower overall corrosion rates than either cold rolled carbon steel or 380 die cast aluminum. But also noticeable are some significant contrasts the relative effects of the nickel and copper contaminants in the atmospheric versus salt spray exposure are reversed, and the effect of both contaminemts is mild in the atmospheric exposure when compared to their effects on the salt spray performance of AZ91 versus the carbon steel panels common to both tests. 

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