KNS烟草烤炉专用钢的研发试制

玉溪新兴钢铁有限公司研发了一种KNS烟草烤炉专用钢,对钢的化学成分、铸坯低倍组织、钢的力学性能、金相显微组织、夹杂物、晶界铜偏析、耐硫酸腐蚀性及高温抗氧化性等进行研究分析。结果表明:钢中添加了Ni、Cr、Cu、Sb等多种微合金耐蚀元素,化学成分均匀,铸坯低倍缺陷级别≤1.0级,低倍组织缺陷少且尺寸小,有利于轧材性能的改善;钢的抗拉强度为460~520 MPa,断后伸长率≥32%,铁素体晶粒度≥10.0级,非金属夹杂物≤1.0级;晶界、晶内铜含量基本一致,在晶界处没有出现铜偏析现象,避免了轧制过程"铜脆"裂纹的发生;耐硫酸腐蚀率为4.6 mm/a,800℃高温氧化跌落损失率为0.57%,具有良好的耐硫酸腐蚀性及抗高温氧化性。     

Crack growth model for pipeline steels exposed to near‐neutral pH groundwater

This paper postulates a crack growth model for pipeline steels in near‐neutral pH soil environments, on the basis of the experimental results reported in literature and the fundamental understanding of the corrosion fatigue crack growth dominated by hydrogen embrittlement mechanism. The comparison with the laboratory data indicates that this model can provide reasonable predictions for the dependence of the crack growth rates on the stress intensity factor, stress ratio, loading frequency, solution pH and electrochemical potential.     

Electrochemical and corrosion behaviour of stainless steels 316L and 317L in chloridised ammonium sulphate solution

Abstract

The corrosion of stainless steel alloys 316L and 317L in chloridised ammonium sulphate solution at 100°C and varying pH was investigated. Alloy 316L was found to be an adequate material for use in naturally aerated solution within the pH range of 5·4–7·4. At low potentials (<0·23 V) and a high potential (0·75 V), alloy 317L shows better performance. It also exhibits better pitting resistance at high potential, however, in the potential range of 0·23–0·45 V, alloy 316L shows better corrosion resistance. The dissolution of the Mo oxide species is proposed to be the reason for the weak performance of alloy 317L in the potential range of 0·23–0·45 V.

On a examiné la corrosion des aciers inoxydables 316L et 317L dans une solution chlorée de sulfate d’ammonium à 100°C et à pH variable. On a trouvé que l’alliage 316L était un matériel adéquat pour utilisation dans une solution aérée naturellement dans la gamme de pH de 5·4 à 7·4. Aux faibles potentiels (<0·23 V) et à potentiel élevé (0·75 V), l’alliage 317L montrait une meilleure performance. Il exhibait également une meilleure résistance à la corrosion par piqûres à potentiel élevé. Cependant, dans la gamme de potentiel de 0·23–0·45 V, l’alliage 316L montrait une meilleure résistance à la corrosion. On propose la dissolution d’une espèce d’oxyde de Mo comme étant la raison pour la faible performance de l’alliage 317L dans la gamme de potentiel de 0·23–0·45 V.     

Current Induced at Conduit Wall by Molten Salt Flowing Across a Magnetic Field

Activation cross sections for mercury isotopes have been measured at neutron energy between 13.4 and 14.9 MeV by means of the activation method using Fusion Neutronics Source (FNS) at Japan Atomic Energy Research Institute (JAERI). Measured cross sections are those of ¹⁹⁶Hg(n, 2n)^195m,^gHg, ¹⁹⁸Hg(n, 2n)^197m,^gHg, ¹⁹⁸Hg(n, p) ¹⁹⁸gAu, ¹⁹⁹Hg(n, p)¹⁹⁹Au, ²⁰⁰Hg(n, p)^200m,gAu, ²⁰¹Hg(n, p)²⁰¹Au, ²⁰²Hg(n, p)²⁰²Au, ²⁰⁴Hg(n, 2n)²⁰³Hg and ²⁰⁴Hg(n, p)²⁰⁴Au reactions. The cross sections of the ²⁰²Hg(n, p)²⁰²Au and ²⁰⁴Hg(n, p)²⁰⁴Au reactions were measured for the first time. For the ¹⁹⁶Hg(n, 2n) ^195m,^gHg, ¹⁹⁸Hg(n, 2n)^197m,^gHg, ¹⁹⁸Hg(n, p)^198gAu and ¹⁹⁹Hg(n, p)¹⁹⁹Au reactions, the cross sections at plural neutron energies were measured for the first time. The present data were compared with the experimental data reported previously and the recent evaluations, and it was shown that some evaluations need to be improved.     

Fretting fatigue behaviour of Ni-free high-nitrogen stainless steel in a simulated body fluid

Abstract

Fretting fatigue behaviour of Ni-free high-nitrogen steel (HNS) with a yield strength of about 800 MPa, which was prepared by nitrogen gas pressurized electroslag remelting, was studied in air and in phosphate-buffered saline (PBS(-)). For comparison, fretting fatigue behaviour of cold-rolled SUS316L steel (SUS316L(CR)) with similar yield strength was examined. The plain fatigue limit of HNS was slightly lower than that of SUS316L(CR) although the former had a higher tensile strength than the latter. The fretting fatigue limit of HNS was higher than that of SUS316L(CR) both in air and in PBS(-). A decrease in fatigue limit of HNS by fretting was significantly smaller than that of SUS316L(CR) in both environments, indicating that HNS has better fretting fatigue resistance than SUS316L(CR). The decrease in fatigue limit by fretting is discussed taking into account the effect of friction stress due to fretting and the additional influences of wear, tribocorrosion and plastic deformation in the fretted area.