Ispitivanje zavarljivosti čelika TStE 420 nakon simulacije toplinskog ciklusa zavarivanja

The paper presents a short description and overview of the weld thermal cycle simulation methods. An experimental investigation on the weld cycle simulated specimens is predicted by a plan of experiment using single cycle simulation. The obtained hardness results are compared with double cycle simulated specimens results of individual points in the heat-affected zone. Beside that, the characteristic microstructures of points in the heat-affected zone after a single weld thermal cycle simulation are given. A thermal simulation method is suitable for different weldability examinations. In this paper, the authors would like to investigate the maximal hardness of individual points in the weld joint what is important when considering cold cracking sensitivity.U radu se daje kratak opis i pregled metoda simulacije toplinskog ciklusa zavarivanja. Planom eksperimenta je predviđeno eksperimentalno istraživanje na toplinski cikliranim uzorcima. Mjerenjem dobiveni rezultati tvrdoće nakon jednostruke simulacije toplinskog ciklusa u zoni utjecaja topline su uspoređeni s rezultatima nakon dvostruke simulacije toplinskog ciklusa. Pored toga, u radu su prikazane karakteristične mikrostrukture pojedinih točaka u zoni utjecaja topline nakon jednostruke simulacije toplinskog ciklusa zavarivanja. Simulacija toplinskog ciklusa je prikladna za različita ispitivanja zavarljivosti, a u ovom su radu autori željeli istražiti maksimalno očekivane tvrdoće pojedinih točaka u zoni utjecaja topline što je važno kod razmatranja osjetljivosti prema hladnim pukotinama

Successfully opening an in-stent chronic total occlusion lesion of the right coronary artery in a patient with peripheral artery disease

Introduction: There are limited study data available of the effects of peripheral artery disease (PAD) on patients undergoing chronic total occlusion (CTO) percutaneous coronary intervention (PCI). According to the PROGRESS-CTO Registry results patients with PAD undergoing CTO PCI have more comorbidities, more complex lesions and lower procedural success.1-3 We present the case of successful opening in stent CTO lesion of right coronary artery (RCA) in patient with PAD. Case report: 59-year-old man with a known history of a coronary vessel disease and PAD presented to our department due to frequent episodes of chest pain under minimal exercise and claudication and pain in the buttocks. The coronary angiography showed unchanged exam in left coronary basin. The RCA was completely occluded in segment two right in the area of the stent that was implanted eight years before. We found collaterals from the left coronary artery system and signs of calcification and autocollaterals for the distal segment of RCA, so the diagnostically criteria of a CTO were fulfilled. Because of the present symptoms of the patient and evidence for vital myocardium by echocardiography and myocardial scintigraphy revascularization of the CTO was performed. An AL 0.75 6F guidance catheter was used and the standard antegrade wire escalation technique attempted. A Turnpike Spiral catheter was inserted with the help of a ASAHI Fielder XT-A wire which was exchanged to an ASAHI Gaia Second which allowed the successful recanalization. Balloon angioplasty was performed with Abbot Traveler 1.5/15mm, Medtronic Euphora 2.57/15mm. Two sirolimus eluting stents (Terumo Ultimaster 3.0/38 mm and Ultimaster 3.0/30 mm) were successfully implanted with very good angiographic result. Three months later, chronic total occlusion of the left external iliac artery was treated successfully by percutaneous intervention and control coronary angiography showed unchanged exam in RCA. Conclusion: Our experience in this case demonstrates the feasibility of recanalization of an in-stent CTO in the patient with PAD and three months follow up showed improved of angina and quality of life. There is a definite and strong correlation between PAD and CAD. A concurrent PAD diagnosis is associated with higher rates of adverse outcomes following CTO PCI which requires additional monitoring

Ispitivanje zavarljivosti čelika TStE 420 nakon simulacije toplinskog ciklusa zavarivanja

The paper presents a short description and overview of the weld thermal cycle simulation methods. An experimental investigation on the weld cycle simulated specimens is predicted by a plan of experiment using single cycle simulation. The obtained hardness results are compared with double cycle simulated specimens results of individual points in the heat-affected zone. Beside that, the characteristic microstructures of points in the heat-affected zone after a single weld thermal cycle simulation are given. A thermal simulation method is suitable for different weldability examinations. In this paper, the authors would like to investigate the maximal hardness of individual points in the weld joint what is important when considering cold cracking sensitivity