Loading devices

Cormet provides various kinds of loading devices for stress corrosion cracking (SCC), sulphide stress cracking (SSCC), hydrogen induced cracking (HIC), fracture mechanical and fatigue studies.

Proof Ring is the most simple and affordable loading device. We offer 10-20 kN and 20-38 kN capacity proof rings. The most common specimen type is the round tensile specimen that goes through the test cell lids. Flat tensile specimen holders are available and we also make custom specimen holders for your need. A load cell can be added to proof ring to monitor test load during longer tests and when creep can be an issue.

Proof ring is quite versatile and can be used to tackle different kinds of constant load needs. We also offer loadcells to proof rings that enable you to monitor the load during the test. Loadcell allows for easy load level adjustment and can also tell if sample extends during the test as that results in load drop.

We also have proof ring for elevated temperature and pressure applications. Tiny autoclave is placed in the middle of the proof ring. This is practical solution for H2S testing as the whole system can be placed in regular draft cabinet at H2S lab. As seen on the right side it can be equipped with gas in/out lines. Sample is isolated from the small autoclave enabling electrochemistry measurements.

Cormet’s workhorse for stress corrosion cracking tests is a PC operated electromechanical loading device. It can perform Slow Strain Rate Tests (SSRT), Constant Load (CL) tests and Low Frequency Cyclic Fatigue (LFCF) tests. The loading device can be used in ambient temperature, autoclave and high temperature gas environments. There are several models available of which the 25 kN and 50 kN instruments are the most popular. The operational principle of the versatile and flexible controlling software is based on sequenced load patterns that can be combined and connected in series.

The highest cyclic loading frequency of Cormet’s electromechanical instrument is about 0.1 Hz depending on the amplitude, loading mode and loading pattern. Servohydraulic or electrically operated loading instruments are needed for the higher cyclic frequencies. Cormet can integrate an autoclave into such a loading device or integrate the servohydraulic actuator with a Cormet autoclave.

The core of the HIC instrument is a glass container in which the specimens are assembled. However, the accessories including gas volume flow meters, water traps, a draft cabinet, ventilation and gas neutralization tools make the instrument more complicated. The HIC testing procedures are described in NACE TM0284-2016.

Operation of four point bending (FPB) instruments is described in NACE TM0177-2016 Method B, ASTM G 39-2011 and ISO 7539-2 (1989). The FPB tests are often performed in HIC testing containers.

Constant-load instruments are used for evaluation of critical stress in a given environment using the Time-to-Failure (TTF) value as a testing result. Standards NACE TM0177-2016 Method A and ASTM G 47 – 98 (2004) describe how to perform the constant load tests. In addition to the simple proof rings, Cormet offers spring loaded and motor controlled constant load instruments.

The effect of high pressure hydrogen on material properties is an interesting topic. Tensile tests and fatigue tests can be performed using regular loading devices and specimens in pressure chambers. It is also possible to use hollow tensile and fatigue specimens that are pressurised internally with hydrogen. The crack growth and fracture mechanical tests must be performed using regular precracked notched specimens.

Have a look at our references related to this product!

2019

China Electronic Product Reliability and Enviromental Testing Research Institute, China

Instrument

38kN proof rings tailored to customers needs

Application

Large scale real environment material testing
2018

Constellium, France

Instrument

Four point bending frames

Application

SCC studies

Curtin University, Australia

Instrument

38kN Proof Rings with H2S gas management system

Application

SCC studied in H2S environment

Intertek, Switzerland

Instrument

Four point bending frames

Application

SCC tests

Norwegian University of Science and Technology, Norway

Instrument

50kN SSRT machine with glass test cell

Application

SCC studies

OCAS (ArcelorMittal), Belgium

Instrument

25kN Tabletop SSRT

Application

Hydrogen assisted cracking
2017

University of Manchester, United Kingdom

Instrument

25kN SSRT autoclave

Application

SCC studies, 350C / 20MPa

VUZ - Welding Research Institute, Slovakia

Instrument

SSRT autoclave and loop for super-critical water and CO2

Application

SCC studies, 650C / 35MPa
2016

BAM, Germany

Instrument

100kN SSRT machine for both compression and tension

Application

SCC studies

VTT Technical Research Centre of Finland, Finland

Instrument

4pcs of 25kN SSRT autoclaves

Application

SCC studies in water and gas environments
2015

Research Centre, India, India

Instrument

25kN SSRT autoclave with DCPD

Application

SCC Studies In Nuclear Environment