Prediction and elimination of galling in forming galvanized advanced high strength steels (AHSS)

Prediction and elimination of galling in forming galvanized advanced high strength steels (AHSS)

Bibliographic Details
Main Author: Kim, Hyunok
Language:English
Published: The Ohio State University / OhioLINK 2008
Subjects:
Engineering
Galling
Stamping
Advanced High Strength Steels (AHSS)
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=osu1204515296
id ndltd-OhioLink-oai-etd.ohiolink.edu-osu1204515296
record_format oai_dc
spelling ndltd-OhioLink-oai-etd.ohiolink.edu-osu12045152962021-08-03T05:53:19Z Prediction and elimination of galling in forming galvanized advanced high strength steels (AHSS) Kim, Hyunok Engineering Galling Stamping Advanced High Strength Steels (AHSS) To improve crash worthiness and fuel economy, the automotive industry is using increasingly Advanced High Strength Steels (AHSS). In addition having limited formability, compared to mild steels, AHSS require high pressures at the tool-workpiece interface. This leads to frequent lubricant film break down and galling as well as reduction in tool life, resulting in a considerable challenge to stamping engineers. Galling is a form of adhesive wear and the economic impact of galling upon stamping production is significant due to the increase of scrap rate and die maintenance cost.The major objective of this study is to predict and reduce galling in forming galvanized AHSS. For this purpose, a preliminary model was developed to predict the severity of galling for given lubricants, die materials and coatings in forming galvanized AHSS.In this study, Finite Element Analysis (FEA) of selected stamping operations with AHSS was conducted to determine the critical pressure conditions that exist in practical stamping. Thus, an attempt was made to develop laboratory tribotests, e.g. Twist Compression Test (TCT), Deep Drawing (DDT) and Strip Drawing Test (SDT) that emulate practical stamping conditions. By using these tribotests, the performance of lubricants, die materials and coatings was evaluated for various grades of AHSS in terms of coefficient of friction (COF) and galling. The results of this study helped to develop a preliminary model for predicting galling by considering the empirical relationships between important tribological parameters (e.g. interface pressure, sliding length, surface roughness, lubricant viscosity, hardness of zinc-coatings and tool coatings) and galling in forming galvanized AHSS. This model was applied to estimate the total number of parts that can be formed before severe galling occurs. Therefore, this model can offer a cost effective way to select practical and best combinations of lubricant, tool material and tool coating for reducing galling in forming galvanized AHSS. In addition, it can be further developed for use as a scheduling tool for the die maintenance before galling occurs, thus the unexpected downtime of stamping process can be eliminated. 2008-03-18 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1204515296 http://rave.ohiolink.edu/etdc/view?acc_num=osu1204515296 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection NDLTD
language English
sources NDLTD
topic Engineering
Galling
Stamping
Advanced High Strength Steels (AHSS)
spellingShingle Engineering
Galling
Stamping
Advanced High Strength Steels (AHSS)
Kim, Hyunok
Prediction and elimination of galling in forming galvanized advanced high strength steels (AHSS)
author Kim, Hyunok
author_facet Kim, Hyunok
author_sort Kim, Hyunok
title Prediction and elimination of galling in forming galvanized advanced high strength steels (AHSS)
title_short Prediction and elimination of galling in forming galvanized advanced high strength steels (AHSS)
title_full Prediction and elimination of galling in forming galvanized advanced high strength steels (AHSS)
title_fullStr Prediction and elimination of galling in forming galvanized advanced high strength steels (AHSS)
title_full_unstemmed Prediction and elimination of galling in forming galvanized advanced high strength steels (AHSS)
title_sort prediction and elimination of galling in forming galvanized advanced high strength steels (ahss)
publisher The Ohio State University / OhioLINK
publishDate 2008
url http://rave.ohiolink.edu/etdc/view?acc_num=osu1204515296
work_keys_str_mv AT kimhyunok predictionandeliminationofgallinginforminggalvanizedadvancedhighstrengthsteelsahss
_version_ 1719427208126136320

Similar Items