Effect of surface treatment by plastic deformation on the gas liberation and hydrogen penetrability of kh18N10T steel

1978 ◽  
Vol 14 (3) ◽  
pp. 257-259
Author(s):  
Yu. I. Belyakov ◽  
A. V. Ivanov ◽  
V. A. Kurakin ◽  
A. A. Kurdyumov ◽  
A. I. Kholodov
2020 ◽  
Vol 867 ◽  
pp. 125-133
Author(s):  
Achmad Syaifudin ◽  
Julendra Bambang Ariatedja ◽  
Katsuhiko Sasaki

During the implantation process, an expandable balloon stent undergoes a change in mesh shape with a high strain rate. Permanent mesh shape changes to the stents indicate plastic deformation has occurred. On a micro-scale, plastic deformation has significant influence when interacting with the soft tissue of human blood vessels. This experimental study aims to investigate the effect of surface treatment and cutting orientation on the changes in surface roughness that definitely occurs when a stent deployed. To study the effect of surface treatment, two types of surface treatment were applied after surface polishing, i.e. etching and electropolishing. Surface polishing is carried out to enable microscopic observation. As for examining the effect of cutting orientation, the plate is cut in lateral and longitudinal orientation against the predicted-rolling direction of 316L sheet-type of stainless steel. An intermittent tensile test is conducted to obtain information about the changes in surface roughness. The surface observation is carried out three times on a similar surface of testpiece after reaching plastic deformation. The experimental study shows that the orientation of raw material has an insignificant effect on the changes in stent surface roughness. As for the surface treatments, electropolishing tended to decrease the tensile property of material.


2020 ◽  
pp. 252-255
Author(s):  
V.I. Bolobov ◽  
V.S. Bochkov ◽  
E.V. Akhmerov ◽  
V.A. Plashchinsky ◽  
E.A. Krivokrisenko E.A.

On the example of Hadfield steel, as the most common material of fast-wearing parts of mining equipment, the effect of surface hardening by plastic deformation on their impact and abrasive wear resistance is considered. Wear test is conducted on magnetic ironstone as typical representative of abrasive and hard rock. As result of wear of initial samples with hardness of ∼200 HB and samples pre-hardened with different intensities to the hardness of 300, 337 and 368 HB, it is found that during the initial testing period, the initial samples pass the “self-cold-work hardening” stage with increase in hardness to ∼250 HB, which remains virtually unchanged during further tests; the hardness of the pre-hardened samples does not change significantly throughout the tests. It is established that the rate of impact-abrasive wear of pre-hardened samples is significantly (up to 1.4 times) lower than the original ones that are not subjected to plastic deformation, and decreases with increasing degree of cold-work hardening. Preliminary surface hardening by plastic deformation can serve as effective way to increase the service life of fast-wearing working parts of mining equipment.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Amr M. Elnaghy ◽  
Ayman Mandorah ◽  
Ali H. Hassan ◽  
Alaa Elshazli ◽  
Shaymaa Elsaka

Abstract Background To evaluate the effect of surface treatments on the push-out bond strength of Biodentine (BD) and white mineral trioxide aggregate (WMTA) to fiber posts. Methods Two brands of fiber posts were used: Reblida post; RP and RelyX post; RX. Each type of post (n = 80/group) was divided into four groups (n = 20/group) and exposed to surface treatment as follows: Control (no treatment), sandblasting (SB), hydrofluoric acid (HF), and TiF4 4 wt/v%. Each group was further subdivided into two subgroups (n = 10/subgroup) based on the type of CSCs used as follows: Subgroup A: BD and Subgroup B: WMTA. Push-out bond strength of BD and WMTA to glass fiber posts was assessed. Data were statistically analyzed using three-way ANOVA and Tukey’s test. A Weibull analysis was performed on the push-out bond strength data. Results BD showed higher bond strength than WMTA (P < 0.001). The push-out bond strength for posts treated with TiF4 4 wt/v% showed greater bond strength than the other surface treatments (P < 0.05). The BD/RP-TiF4 4 wt/v% showed the greater characteristic bond strength (σ0) (15.93) compared with the other groups. Surface treatments modified the surface topography of glass fiber posts. Conclusions The BD/RP-TiF4 4 wt/v% showed greater bond strength compared with the other groups. The TiF4 4 wt/v% surface treatment enhanced the bond strength of BD and WMTA to glass fiber posts than the other treatments. Surface treatment of fiber post with TiF4 4 wt/v% could be used to improve the bond strength with calcium silicate-based cements.


Author(s):  
M Ghavam ◽  
M Naeemi ◽  
SS Hashemikamangar ◽  
H Ebrahimi ◽  
MJ Kharazifard

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