Dynamic fracture initiation behavior of an HY-100 steel. [0. 19C-0. 29Mn-0. 006P-0. 014S-0. 23Si-2. 56Ni-1. 68Cr-0. 45Mo-0. 013Pb]

Journal Article · Thu Apr 01 04:00:00 EST 1993 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

OSTI ID:6518526

Lee, Sunghak; Rhyu, Je Won ^[1]; Cho, Kyungmox ^[2]; Duffy, J ^[3]

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1. Pohang Inst. of Science and Technology (Korea, Republic of)
2. Pusan National Univ. (Korea, Republic of)
3. Brown Univ., Providence, RI (United States)

An investigation was conducted into the effects of test temperature and loading rate on the initiation of plane strain fracture of an HY-100 steel. Fracture toughness tests were conducted using fatigue precracked round bars loaded in tension to produce a quasi-static stress intensity rate of [dot K][sub I] = 1 MPa [radical]m/s and a dynamic rate of [dot K][sub I] = 2 [times] 10[sup 6] MPa [radical]m/s. Testing temperatures covered the range from [minus]150C to 200C, which encompasses fracture initiation modes involving quasi-cleavage to fully ductile fracture. The results of toughness tests show that the lower-shelf values of fracture toughness were substantially independent of loading rate, while the dynamic values exceeded the quasi-static values by about 50% on the upper shelf. In analyzing these results, phenomenological fracture initiation models were adopted based on the requirement that, for fracture to occur, a critical strain or stress must be achieved over a critical distance. In separate tests, the observation of microfracture processes was investigated using fractography and an in situ scanning electron microscope (SEM) fracture technique. The layered appearance of the fracture surfaces was found to be associated with a banded structure which generally contains many MnS inclusions, probably resulting in a reduction of the fracture toughness values.

• OSTI ID: 6518526
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Journal Name: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States) Vol. 24A:4; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
CHROMIUM ALLOYS
ELECTRON MICROSCOPY
FATIGUE
FRACTOGRAPHY
FRACTURE PROPERTIES
HIGH ALLOY STEELS
IRON ALLOYS
IRON BASE ALLOYS
LOW CARBON-HIGH ALLOY STEELS
MECHANICAL PROPERTIES
MICROSCOPY
NICKEL ALLOYS
NICKEL STEELS
NICKEL-CHROMIUM STEELS
SCANNING ELECTRON MICROSCOPY
STAINLESS STEELS
STEELS
TEMPERATURE DEPENDENCE