scholarly journals Modeling and Analysis of Effective Case Depth on Meshing Strength of Internal Gear Transmissions

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Dezheng Liu ◽  
Yan Li ◽  
Zhongren Wang ◽  
You Wang ◽  
Yu Wang
Keyword(s):  
Heat Treatment ◽  
Lower Surface ◽  
Case Depth ◽  
Gear Transmission ◽  
Modeling And Analysis ◽  
Depth Direction ◽  
Carburized Gear ◽  
Internal Gear ◽  
Effective Case Depth ◽  
Effective Case

The effective case depth (ECD) plays an important role in the meshing strength of internal gear transmissions. Carburizing quenching heat treatment is commonly used to enhance gear strength and wear resistance. However, the different ECDs in internal and external gears caused by heat treatment significantly affect the meshing strength, causing vibration, reducing gear service life, and hastening malfunction in internal gear transmission. In this study, we conducted an investigation of different ECDs by the heat treatment of carburized gear pairs by numerical simulation with the finite element method (FEM) and experiment tests. We analyzed three different carburized layer models, with the ECD in the internal gear being greater than, less than, and equal to the ECD in the external gear. In addition, we investigated the ability to distinguish between hardness gradients in gear teeth by dividing the carburized depth into seven layers to improve modeling accuracy. Results revealed that the meshing strength of internal gear transmission could be significantly enhanced by adopting the model with the ECD in the internal gear being less than the ECD in the external gear, and moreover, the shear stress of carburized gears initially increased and then decreased along with depth direction, and the maximum value appeared in the middle of the lower surface.

Hardness Distribution and Effective Case Depth of Low Carbon Steel after Pack Carburizing Process under Different Carburizer

2015 ◽  
Vol 776 ◽  
pp. 201-207 ◽  
Author(s):  
Dewa Ngakan Ketut Putra Negara ◽  
I. Dewa Made Krisnha Muku ◽  
I. Ketut Gede Sugita ◽  
I. Made Astika ◽  
I. Wayan Mustika ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Low Carbon Steel ◽  
Case Depth ◽  
Bamboo Charcoal ◽  
Hardness Distribution ◽  
Low Carbon ◽  
Bone Charcoal ◽  
Carburizing Process ◽  
Effective Case Depth ◽  
Effective Case

This research is concerned with the effect of different carburizers on hardness distribution, effective case depth and microstructure of low carbon steel after pack carburizing process. Carburizers to be used were combination of energizer (BaCO3), goat bone charcoal and bamboo charcoal with five different compositions. The specimens were heated to temperature of 950°C, soaked at the temperature for 4 hours and quenched in the water. After the process, microstructures of specimen were observed, the hardness was measured using Vikers method and effective case depths were calculated. The results obtained showed that for all types of carburizer used, the hardness were scattered from surface to the core with lower hardness level. Carburizer composition of 20% BaCO3 + 80% goat bone charcoal produced the highest hardness ( 789.273 HV1) at 0.2 mm from the surface, however, it yielded the lowest effective case depth (0.52 mm). The highest effective case depth of 1 mm was obtained using carburizer composition of 20% BaCO3 + 60% goat bone charcoal + 20% bamboo charcoal. Meanwhile, the original structures of raw material which consist of ferrite and pearlite transformed to hard martensite constituent in the surface after pack carburizing.

scholarly journals Investigation of hardness behavior after carburizing and hardening of 15CrNi6 steel

2021 ◽  
Vol 349 ◽  
pp. 02006
Author(s):  
Arsenis Dragatsis ◽  
Leonidas Fragkos-Livanios ◽  
Dimitris G. Papageorgiou ◽  
Carmen Medrea
Keyword(s):  
Chemical Composition ◽  
Case Depth ◽  
Holding Time ◽  
Case Hardening ◽  
Similar Chemical ◽  
Practical Information ◽  
The Impact ◽  
Substrate Hardness ◽  
Effective Case Depth ◽  
Effective Case

DIN 15CrNi6 is the most representative grade of the case-hardened steels. The present work analyses the influence of carburizing time on hardness of the specific steel. Specimens with similar chemical composition were heated at 900°C in liquid carbonaceous media for one, two, three and four hours, correspondingly. Then samples were oil quenched and tempered at 180°C for two hours. Microhardness was measured across the carburized zone and case profiles were acquired. The effective case depth was determined as function of carburizing holding time. Core macro hardness was carried out and the impact of holding time on the substrate hardness was discussed. The optimum case depth was defined and the carburizing parameters determined. The hardness control is critical in case hardening practice and results provide practical information to heat treaters, useful both to control the treatment parameters and to minimize the risk of failure.

Verification on Possibility of Nitrogen Diffusion into Steel by High Temperature N-Quench

2019 ◽  
Vol 395 ◽  
pp. 124-132
Author(s):  
Atsushi Nakamura ◽  
Koichiro Nambu ◽  
Masahiro Okumiya
Keyword(s):  
Phase Region ◽  
Case Depth ◽  
Heating Furnace ◽  
Infrared Heating ◽  
Nitrogen Diffusion ◽  
Two Phase ◽  
Conventional Furnace ◽  
Low Distortion ◽  
Effective Case Depth ◽  
Effective Case

N-Quench, which is a new surface heat treatment to infiltrate nitrogen into steel parts followed by quenching to achieve hardening, is gathering attention in the nitriding field as it affords low distortion while maintaining a higher effective case depth (ECD) compared with conventional nitriding. N-Quench is conducted mainly between 680°C and 800°C, where the two-phase region of ferrite and austenite exists in the Fe-N phase diagram. However, a few studies have reported on nitriding at temperatures higher than 800°C due to decomposition of NH3, which is a key source of nitrogen infiltration. Our results revealed that in a conventional furnace such as resistance heating furnace, no nitrogen infiltrated the specimen at 930°C, which is the general carburizing temperature. On the other hand, in the infrared heating furnace, nitrogen infiltrated the specimen at 930°C successfully with lesser NH3 introduction than that required by the conventional furnace. Therefore, in this study, the limit of NH3 decomposition is assessed and possibility of extending the applicability of N-Quench, especially increasing the ECD while maintaining a low distortion, is examined.

scholarly journals Development of Nondestructive Inspection Instrument of Effective Case Depth.

DENKI-SEIKO ◽  
1991 ◽  
Vol 62 (3) ◽  
pp. 175-182
Author(s):  
Toshio Endoh ◽  
Tomikazu Yagi ◽  
Ken-ichi Takata
Keyword(s):  
Nondestructive Inspection ◽  
Case Depth ◽  
Effective Case Depth ◽  
Effective Case
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