Nastanek poškodb v jeklu pri globokem vleku

magistrsko delo

Neja Rokavec (Author), Aleš Nagode (Mentor)

Abstract

V okviru magistrskega dela smo raziskovali problem nastanka napak duktilnega jekla, ki nastanejo med procesom globokega vleka. Globoki vlek je eden najpomembnejših procesov hladnega preoblikovanja pločevine. Uporabljamo ga predvsem pri velikoserijski proizvodnji pločevinastih izdelkov. Ker je stopnja deformacije pri postopku globokega vleka zelo visoka, se lahko na izdelku pojavijo napake. Analizirali smo dva jeklena trakova in naredili literarni pregled s področja napak in poškodb pri globokem vleku, s ciljem, da bi ugotovili vzrok za nastanek napak, ki se pojavljajo med preoblikovanjem enega od trakov. Za nastanek poškodb v jeklu med globokim vlekom je možnih veliko vzrokov, ki so lahko povezani z orodjem ali materialom. Glede na to, da so se poškodbe pojavile le na določenih jeklenih trakovih pri uporabi enakega orodja, smo se v okviru magistrskega dela osredotočili na karakterizacijo jekel. Trakova sta izdelana iz jekla za globoki vlek DC07, ki ustreza standardu SIST EN 10130. Podrobneje smo analizirali kemijsko sestavo, mikrostrukturo, teksturiranost in mehanske lastnosti jeklenih trakov. Poleg tega smo raziskali še dodaten pomemben dejavnik, ki vpliva na globoki vlek, to je anizotropija jeklenih trakov, ki se pojavi zaradi smeri valjanja. Glavni povzročitelj slednjega je različna mikrostruktura v posameznih oseh. Ugotovljeno je bilo, da sta tako kemijska sestava kot teksturiranost jeklenih trakov zelo podobni in ne vplivata na nastanek napak. Opravljeni mehanski preizkusi pa dokazujejo, da ima trak A boljše karakteristike za globoki vlek. Cilj naloge je bil postaviti pravilno razlago za pojav napak pri postopku globokega vleka in na podlagi teh ugotovitev izboljšati kakovost izdelka. Z opravljenimi analizami smo ugotovili, da je bil naš preizkus uspešen, zato predpostavljamo, da se pri novo nastalih izdelkih napake ne bodo več pojavljale.

Keywords

globoki vlek;anizotropija;teksture;mehanske lastnosti;

Data

Language:	Slovenian
Year of publishing:	2020
Typology:	2.09 - Master's Thesis
Organization:	UL NTF - Faculty of Natural Sciences and Engineering
Publisher:	[N. Rokavec]
UDC:	669
COBISS:	16164355
Views:	548
Downloads:	157
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	damage development in steel during deep drawing
Secondary abstract:	Deep drawing is one of the most important processes of cold sheet metal transformation mainly used in large-scale production. Since deformation rate of the deep drawing process is very high, defects can occur on the product. As part of the master thesis, we investigated the formation of ductile steel defects that occur during the deep drawing process. To determine the cause of the defected steel band literary examination of defects and damages in deep traction was conducted, after analysis of the two steel bands (defected and non-defected). During deep drawing, the steel damage may be in conjunction with the tool or material. The characterization of steel was done since damages occurred only on certain steel bands, although the same tool was used during the process. The bands were made of DC07 deep drawing steel, which complies with the SIST EN 10130 standard. Microstructure, texture, mechanical properties, and chemical composition analysis were conducted on the steel bands. What is more, we investigated the anisotropy of steel bands that occurs due to the rolling direction. The main cause of the latter is the different microstructure in individual axes. It was found that both the chemical composition and the texture of the steel bands are very similar and do not affect the occurrence of defects. The mechanical tests prove that the A-band has better characteristics for deep drawing. This study aimed to find the cause of the defects in the deep drawing process and consequently to improve the quality of the product. Considering our findings, we assume that defects in new products will not show up.
Secondary keywords:	deep drawing;anisotropy;texture;mechanical properties;
Type (COBISS):	Master's thesis/paper
Study programme:	0
Thesis comment:	Univ. v Ljubljani, Naravoslovnotehniška fak., Odd. za materiale in metalurgijo
Pages:	XVI, 50 f.
ID:	11705542