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ML00137 - Mar.2021

Brittle Fracture of a 15-5 PH Valve Spring

Aspect of the broken spring. The wire is 1 1/2" diameter and the ourter diameter of the spirals is 12 1/2", in a 20" height spring. It was broken in several pieces.

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Aspect of the broken spring. The is 1 1/2" diameter and the ourter diameter of the spirals is 12 1/2", in a 20" height spring. It was broken in several pieces.
M

Material

Precipitation Hardened Stainless Steel
  • UNS S15500
  • ALLOY 15-5 PH
Ds

Description

After three years in service in a oil offloading , the spring was detected to be broken in a brittle way in several pieces. The spring presented, , deposits and underdeposits intergranular that indicate a embrittlement effect. These surface cracks induced a brittle through thickness , transgranular.

C

Chemistry (% in weight)

Spring Analysis

0.033C; 0.36Si; 0.69Mn; 0.031P; 0.006S; 14.0Cr; 5.6Ni; 1.5Mo; 0.36Nb; 1.5Cu; 0.03W; 0.08V.

Associated Images
Aspect of the broken spring. The wire is 1 1/2" diameter and the ourter diameter of the spirals is 12 1/2", in a 20" height spring. It was broken in several pieces.
866
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - General View
Aspect of the fracture of the spring. Close to the surface the fracture presents the aspect of rusted spots.
132
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Fracture
The spring ruptured in several positions. This is the aspect of one of the fractures of the spring. In the initiation of the fracture (top side of the figure) the fracture presents a different morphology.
101
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Brittle Fracture
Microstructure of the spring in a transverse section, presenting an aged martensitic structure.
96
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Martensite
Corroded spots (shallow pits) at the spring surface.
84
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - At the Surface
Corroded spots (shallow pits full of products) at the spring surface.
80
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Corrosion
Corroded spots (shallow pits full of products) at the spring surface.
75
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Corrosion
Micrography of a longitudinal section of the spring indicating that under the deposits there are intergranular cracks initiating at the spring surface.
72
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - As polished micrographyDf - Intergranular Cracking
Micrographic detail of a longitudinal section of the spring indicating that under the deposits there are intergranular cracks initiating at the spring surface.
65
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - As polished micrographyDf - Intergranular Cracking
Micrographic detail of a longitudinal section of the spring indicating that under the deposits there are intergranular cracks initiating at the spring surface.
60
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Intergranular Cracking
Micrography of a longitudinal section of the spring indicating that under the deposits there are intergranular cracks initiating at the spring surface.
57
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Intergranular Cracking
Micrographic detail of a longitudinal section of the spring indicating that under the deposits there are intergranular cracks initiating at the spring surface.
57
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Intergranular Cracking
The scanning electron microscopy image presents the surface of the spring (top of the figure) where it was broken (the fracture is in the bottom of the figure). It is possible to see that there is a product at the surface and the material presents intergranular fracture, suggesting there was a hydrogen embrittlement effect. Important to observe that the material does not present pits.
58
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Fractography by SEMDf - At the Surface
The scanning electron microscopy image presents the fracture surface at the fracture initiation point. The fracture is intergranular.
54
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Fractography by SEMDf - Intergranular Fracture
Image detail presenting the intergranular fracture surface at the fracture initiation point.
46
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Fractography by SEMDf - Intergranular Fracture
Fracture micromechanism changing from intergranular to transgranular, as the fracture is propagating.
45
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Fractography by SEMDf - Fracture
Transition from intergranular to transgranular fracture micromechanisms in the fracture surface.
45
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Fractography by SEMDf - Fracture
Transgranular fracture micromechanism in the final propagation of the fracture. Quasecleavage.
41
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Fractography by SEMDf - Transgranular Fracture
Transgranular fracture micromechanism in the final propagation of the fracture. Quasecleavage.
44
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Fractography by SEMDf - Transgranular Fracture
Transgranular fracture micromechanism in the final propagation of the fracture. Quasecleavage.
42
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Fractography by SEMDf - Transgranular Fracture
Aspect of the fracture surface showing a strong difference between the fracture initiation and fracture propagation. This fracture was sectioned and the micrographies are presented showing the diferences in the fracture morphology.
40
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Fracture
Micrography of a section transverse to the fracture, in the starting point, showing the intergranular morphology of the fracture surface.
38
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Intergranular Fracture
Micrographic detail of the intergranular morphology of the fracture surface, in the starting point of the failure.
40
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Intergranular Fracture
Micrographic detail of the intergranular morphology of the fracture surface, in the starting point of the failure.
34
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Intergranular Fracture
Micrographic detail of the intergranular morphology of the cracking, adjacent to the fracture surface, in the starting point of the failure.
37
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Secondary Cracks
Micrography of a section transverse to the fracture, in fracture propagation, showing the transgranular morphology of the fracture surface.
36
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Transgranular Fracture
Micrographic detail of the transgranular morphology of the fracture surface, in the final propagation of the failure.
37
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Transgranular Fracture
Micrographic detail of the transgranular morphology of the fracture surface, in the final propagation of the failure.
44
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Transgranular Fracture