The restoration of obliterated serial numbers is a problem of common occurrence in the forensic field. Among several restoration techniques, chemical etching is the most frequently used. The present research is aimed at studying the restoration of serial numbers, stamped on 40NiCrMo4 steel plates, by means of chemical etching. Microstructural characterization was firstly carried out to study the plastically deformed regions surrounding the marks. The obliteration was performed by controlled removals of material at increasing depths of erasure, and five etching reagents were considered to analyze their sensitivity and effectiveness. Experimental results revealed that Fry’s reagent was the most sensitive, able to restore erased marks up to 60 lm under the depth of the imprint. The reagent comprising 25 mL HNO3 and 75 mL H2O provided good results, recovering the major numbers of characters. A descriptive statistical analysis was conducted to study the operator’s influence on the recovered marks’ identification.

Restoration of Obliterated Numbers on 40NiCrMo4 Steel by Etching Method: Metallurgical and Statistical Approaches

FORTINI, Annalisa
Primo
;
MERLIN, Mattia;SOFFRITTI, Chiara;GARAGNANI, Gian Luca
Ultimo
2016

Abstract

The restoration of obliterated serial numbers is a problem of common occurrence in the forensic field. Among several restoration techniques, chemical etching is the most frequently used. The present research is aimed at studying the restoration of serial numbers, stamped on 40NiCrMo4 steel plates, by means of chemical etching. Microstructural characterization was firstly carried out to study the plastically deformed regions surrounding the marks. The obliteration was performed by controlled removals of material at increasing depths of erasure, and five etching reagents were considered to analyze their sensitivity and effectiveness. Experimental results revealed that Fry’s reagent was the most sensitive, able to restore erased marks up to 60 lm under the depth of the imprint. The reagent comprising 25 mL HNO3 and 75 mL H2O provided good results, recovering the major numbers of characters. A descriptive statistical analysis was conducted to study the operator’s influence on the recovered marks’ identification.
2016
Fortini, Annalisa; Merlin, Mattia; Soffritti, Chiara; Garagnani, Gian Luca
File in questo prodotto:
File Dimensione Formato  
Fortini_et_al-2016-Journal_of_Forensic_Sciences.pdf

solo gestori archivio

Tipologia: Full text (versione editoriale)
Licenza: NON PUBBLICO - Accesso privato/ristretto
Dimensione 1.84 MB
Formato Adobe PDF
1.84 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
11392_2338917_PRE_Garagnani.pdf

accesso aperto

Tipologia: Pre-print
Licenza: PUBBLICO - Pubblico con Copyright
Dimensione 1.42 MB
Formato Adobe PDF
1.42 MB Adobe PDF Visualizza/Apri

I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/2338917
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 11
  • ???jsp.display-item.citation.isi??? 7
social impact