MORI 190742

[PAGE 1]
Subject HYPODERMIC NEEDLE

The examinution of the samples súbmitted demonstrated that the brass cap f'rom the collapsible tube contained a fragment of a steel hypodermic needle and. that this fragment was identical in every respect to the section of hypodermic needle submitted separately.

Spectrogruphic comparison showed that the relative amounts of residual impurities such as Cr, Ni, Nn, Cu, Mo, etc. are the same in the two sections. They were also found to be iclentical in outer diameter and structure as determined metallographically.

MEMO

AlB 7.51/1132 5/13

[PAGE 4]
Abrassferrule enclosinga rusted endo. a hypodermicneedle,andl/4 inch piececut froma separate one-inch length ofa rusted hypodermic needle were mountediin,bakelite,ground downto presentalongitudinalsection in the. outerwallo theneedle,and polishedfor metallographic examina Both pieces of steelneedle were observe tobe ofkabout the samediameter,butit wasnot possibleto makemeasurementsdueto the rusted condition of the needleend encased in brass.

[PAGE 6]
Longitudinalsection ground part way through the wallofa hollowsteel needle encased in brass. The black areasare voids due to holes rusted throughthesteelfrominsidetowardtheoutside.

[PAGE 7]
Plate 6521

Etched with Nital

Plate6520

Etched with Nital

1000 x

[PAGE 8]
Thisstructureconsistsofscattered spheroids ofcementiteina matrix of, tempered martensite.It.is typicalof,aihigh carbon tool "steelsuchasisusuallyusedfor.hypodermic'need]